Abrash. Color change in the rug field and/or border due to differences in wool or dye batches. The color change is across the width of the rug, left to right, parallel to a weft yarn.
All-Over Design. The design of the field is neither repeated nor regimented such as hunting or tree of life designs.
Aniline Dyes. A direct dye derived from aniline, which is a derivative of coal tar. The first synthetic dye, mauvine, was invented by William Perkins in 1856. By 1870 aniline dyes were inexpensive and widely used. Early dyes were not fast to light or washing.
Animal Stains. Urine or feces. See “Urine Stains.”
Antique. Rugs that are at least 100 years of age.
Area Rug. Any rug that is not cut and installed to cover the floor from wall to wall.
Bast. Woody, cellulosic fibers from the stem of the plant used for weaving. Examples include flax, hemp, or jute.
Binding. The outermost edge of the rug in which thread overlaps the wool essentially making sure the rug does not unravel.
Bleeding. Dye bleeding on rugs can occur when water encounters dyes that are not properly fixed with a mordant. Bleeding also occurs when dyed yarns are not adequately washed to remove excess dye. Usually, a darker color bleeds into an adjacent lighter color. Pigments used to “paint” rugs are almost always subject to bleeding.
Blocking. A stretching process used in correcting rugs that are out of square or do not lie flat.
Boteh. A classic design element for which the well-known paisley motif is derived. Also, referred to as a leaf, a palm, a pear or a pinecone.
Braided. Rugs made from heavy strips of new or used yarn or fabric, which have been braided into thick ropes and are then sewn side-to-side in spirals, ovals, rounds, and oblongs to create a reversible rug.
Brocading. A weaving technique where a pattern is created by ‘floating’ the design over the foundation.
Border. The outermost region in which the binding lies.
Buckling. Ridges or wrinkles in a rug due to weaving defects. It can also be a
result of differential shrinkage on designer border rugs constructed of machine woven carpet.
Carding. In staple yarn manufacture, a process to remove impurities and short, unusable fibers. The fiber is cleaned and aligned to form a continuous untwisted string called a sliver.
Cartoon. The design of a hand-knotted rug represented on graph paper. Each block or square represents a single knot in the pile.
Cartouche. An enclosed area in the field or border containing an inscription, name or date.
Chrome dyes. Modern synthetic dyes that use potassium dichromate as a mordant to create a bond between the dyestuff and the fiber. They are colorfast to wet cleaning.
Chain Stitch. A stitch consisting of successive loops, used for decorative purposes and sometimes to lock the final weft in place at the end of a rug. India produces a type of flatware embroidered rug composed entirely of chain stitch on a cotton canvas foundation. These rugs usually have a lining.
Chemical Wash. A process in which sheen is imparted to the pile of a rug to artificially age the rug. This is produced not only through the action of the chemicals on the colors in the wool, but also by agitation that removes short, staple fibers that tend to absorb light. A lighter chemical wash can be used to mellow the colors.
Closed Back. In Chinese rugs, if the weft is not visible in the back, the rug is “closed back.”
Coir. The fiber comes from the fresh green husk of ripe coconuts. it is an extremely durable hair like fiber that is resistant to sunlight and abrasion. It is used for wall coverings and area rugs.
Color-Fast. When a rugs color does not change over time, use or exposure to the elements.
Color-Run. When the color of a rug runs to another place in the rug it was not originally intended.
Corner Brackets. See “Spandrel.”
Covered Field. A term that describes a field of a rug that is filled with design elements. A covered field is the opposite of an open field.
Creases (fold lines). Rugs are often shipped folded, which can leave lines that require steaming, washing or blocking of the rug.
Creel. The large frame used to hold yarn cones that directly feed yarn to the needles of a tufting machine.
Crocking. A term used to describe excess color rubbing off as the result of improper yarn rinsing, dye penetration, fixation or selection.
Curvilinear. Any rug design that has primarily curving lines. Sometimes referred to as floral designs. For the most part, a higher knot count is associated with this type of design.
Dead Yarn. A pile yarn in a Wilton carpet that remains hidden in the backing structure when not forming a pile tuft.
Delaminatation. The separation of the secondary backing or attached cushion from the primary backing. Can be caused by over use of solvent spotters or the breakdown of latex over time.
Density. A measure of the quality of the rug’s construction that is determined by two factors: the number of knots and the height of the pile in a given area of the rug.
Design. The overall composition of decorative elements of a rug.
Detergent. Technically, any cleansing agent. In popular usage, washing and cleaning agents with a composition other than soap that clean by much of the same mechanisms as soap.
Directional. Rugs that are oriented in a single direction, such as a prayer rug.
Dry Cleaning. This type of cleaning uses organic solvents rather than water and can be used on certain problem rugs. Silk rugs are often dry cleaned to prevent pile distortion or dye bleed.
Dry foam shampoo. A carpet cleaning method using a detergent solution containing only a small amount of water. Generated foam is mechanically worked into the surface of the carpet and loose soil is removed by vacuuming.
Dry Room. A drying room for rugs generally utilizing a series of heaters that will blow dry hot air into the room forcing the air around various locations of the room. The rugs are dried on dry poles with disturbing and exhaust fans increasing the efficiency of the dry room.
Dry Rot. The term applied to the decay of cellulose caused by various kinds of fungi. The fungi feed on the organic materials causing it to become lighter in weight and density, weaker, more brittle and less elastic. The rug foundation will crack when mechanical action is applied.
Dry Soil. The majority of all rug soil is dry and particulate, and easier to remove with dry soil extraction.
Duster. A machine for dry soil removal. Mechanical dusters are required when cleaning a large volume of rugs. Some models consist of an enclosed rotating arm to which leather straps are attached or high-speed vibrators. Some dusting systems use compressed air to remove dry soil.
Dusting. The use of compressed air to rapidly remove dust that has embedded itself deep into a rug. One of the firsts steps in the cleaning process.
Dye. A material used to color fiber, yarn, or textiles with or without the use of a mordant.
Dye Migration. See “Bleeding.”
Edge Bindings. By wrapping several warps at the edges of a rug, an end binding is created. They are used to reinforce part of the rug.
Etching. The loss of pile from a dark colored part of the rug where a corrosive salt was used.
End Finishes. These finishes are used to hold both knots and wefts to prevent them from unraveling off of the rug’s warp strings.
Face. The side of a fabric that is exposed for viewing; the most decorative side of a fabric. Also called the front of the rug.
Fading. Sunlight over time will fade and damage dyes in textiles.
Felt. A fabric of random, matted animal fibers, usually wool, that adheres to each other after a process of kneading and compression.
Felting. This is a tendency of wool fibers to mat and irreversibly entangle when subjected to excessive agitation.
Field. The largest area of a carpet; the central portion enclosed by borders.
Filament. A single continuous strand of natural or synthetic fiber.
Filler. A low-cost material used for extending rubber, plastic or other polymers. Fillers are generally powders of very small particle size. Rug latex laminating compounds contain large amounts of fillers. The most common filler in rug latex is finely powdered calcium carbonate, produced by grinding limestone. Filler will breakdown over time and leave powder on the floor or pad.
Flat weave. A textile woven without pile.
Foundation. The warps and wefts of a pile rug.
Frames. Racks at the back of the Wilton and Axminster looms holding spools from which yarns are fed into the loom. Each frame holds a separate color, thus, a 3-frame Wilton has three colors in the design.
Fringe. The continuation of the warp yarns at each end of a hand-made rug. The ends of a rug are finished in various ways to prevent the wefts and knots from unraveling. Machine-made rugs may have a fringe attached to each end.
Fuzzing. Occurring with lower quality wool, a hairy effect on fabric surface caused by fibers slipping out of yarn bundles during normal use or cleaning. It can sometimes be corrected by shearing.
Garden Panel design. A design in which the field of the rug is divided into square compartments filled with floral motifs. The design is based on the traditional Persian garden.
Ghiordes Knot. Also called a Turkish knot or symmetric knot. See “Symmetric knot.”
Gold Wash. A chemical washing process, usually seen in rugs from Afghanistan, in which the original red color of the pile is bleached out to shades of gold after the weaving process has been completed.
Ground Color. Background color of the field. Also known as field color.
Gul, Gol. A medallion of octagonal or geometric shape used in Turkoman designs. The gul is repeated to form a linear all-over pattern in the field. Each Turkoman tribe has its own specific guls that represent emblems of the tribe. These patterns can also be found in rugs from Pakistan that copy traditional Turkoman designs.
Hand-hooked rugs. Rugs made with different colored yarns that are hooked by hand through a heavy cloth backing, usually jute or cotton. Today, automatic punch guns have replaced the hooking needles. Yarns are anchored one at a time through the backing and are loop pile.
Hatchli. This is a design in which a large cross divides the field of the carpet into quarters. From the Armenian word for cross.
Heather. A multicolor effect provided by blending fibers of different colors prior to spinning rug yarns.
Heatsetting or (Heatset). A yarn manufacturing term for the process whereby heat or steam is applied to the twisted yarn to increase the yarn’s ability to hold its twist over time. This promotes the fiber’s ability to “bounce back” when it is temporarily crushed under foot.
Heddle. A horizontal rod or beam on a loom to which every other warp yarn is attached. This creates a shed through which the weft yarns are passed.
Herati. A common repeating pattern in hand-knotted rugs. Formed by a rosette surrounded by a diamond with small palmettes at its points and curving, tapered, serrated leaves that resemble fish along its side. Also called “Mahi” design.
Hot water extraction. A popular cleaning process that uses hot water and detergent sprayed onto the carpet and immediately removed, along with suspended soils, by a vacuum system.
Hydrogen Peroxide. Colorless oxygen bleach that is fairly safe to use to set bleach wool at 3% concentration only.
Indigo. A natural blue dye that comes from the indigo plant. This vegetable dye was chemically synthesized in 1880.
In-plant Cleaning. Sometimes referred to as immersion or submersion, the rug is completely immersed in water during soil suspension and cleaning. The process is followed by rinsing, squeegeeing, and wringing or extracting and then drying.
Insect Damage. See “Moth damage.”
Jute. A natural cellulosic fiber made from certain plants of the linden family, used for woven carpet construction in the foundation yarns and secondary backing in tufted carpets.
Juval. A Turkoman or Turkish storage bag that measures 6 x 3 feet (183 cm x 91 cm).
Knot. The term used for a strand of wool yarn which is looped around one, two or four warp yarns and then cut to form the pile (surface of carpet).
Knot count. The number of knots per unit of measure.
Kraft Paper. A thick, brown paper that some cleaners use for wrapping clean rugs before delivering them to their customers.
Line. A unit for measuring the knot density in Chinese rugs. Line is the number of knots per linear foot across the width of the rug.
Linen. It is the best known of the bast fibers. All linen fiber is derived from the flax plant. Flax stalks are dried, then the flax is retted by placing it in water for several days or weeks. The linen fibers are removed from the stems, combed, bleached, and made into yarns.
Loom. The frame on which warps are attached and kept taut during the weaving of a rug.
Low moisture cleaning. Cleaning method which uses high production and low moisture, including absorbent compound, absorbent pad, dry foam shampoo, and mist and brush.
Luster. Brightness or reflective quality of fibers, yarns, carpets or fabrics. In oriental rugs, luster is created by chemical washing (luster wash) or by years of foot traffic.
Madder. A plant whose roots are used to make a red to brown dye. Different mordants will result in different colors.
Medallion. A single large enclosed design or series of large designs that appear in the middle of a rug’s field.
Mihrab. A prayer niche in a mosque depicted as an arch in prayer rugs.
Millefleurs. A design in which many small flowers are repeated throughout the field of the rug. French for “a thousand flowers.”
Mist and Brush. A rug cleaning method which is a low moisture and low residue method to clean rugs. A cleaning solution is sprayed over the rug and then is agitated with a machine using counter-rotating brushes.
Mordant. A compound used to create a chemical bond between the dye stuff and the fiber. The shade and hue of the dye is affected by the type of mordant used.
Moth Damage. Carpet moths and beetles feed on the keratin found in wool when the insects are in a larval state.
Mottled. Marked with blotches or spots of different colors or shades.
Narrow carpet. Woven carpet less than six feet wide, as distinguished from broadloom.
Natural dyes. These dyes are derived from plant or insect material. They tend to mellow with age and are highly regarded by oriental rug experts.
Needlepoint rugs. Portuguese needlepoint rugs began in the 15th century and are made of wool yarns on a woven jute foundation. Contemporary Chinese needlepoint rugs are made on a synthetic foundation material with wool face yarns.
Node. Viewed from the back, one loop of a hand-tied knot wrapped around a warp.
Nylon. Synthetic thermoplastic of the polyamide family widely used as carpet face yarn in either Bulk Continuous Filament (BCF) or staple yarn form.
Open back. The wefts are visible on the back of Chinese rugs.
Open field. A solid-colored ground with or without a simple medallion and corner design. The field is not filled or covered with design elements.
Oriental rug. All hand-knotted pile rugs regardless of origin. The term is now used to include flat-woven rugs from the Near East and Asia.
Overcasting. The wrapping of the bundle of terminal warps that form the sides of the rug. The materials most commonly used are wool, cotton, goat hair and silk. This term is also used to refer to a stick used to secure the ends from raveling.
Over-dyed. This refers to a treatment of rugs that was popular from the 1920s to the 1950s. Certain rugs, particularly the American Sarouk, were heavily chemically washed to remove a rose field color, then over-dyed a maroon color. This over-dying is colorfast but can become mottled as the rug begins to wear.
Oxidation. Rugs with an ivory or off-white color can yellow with age.
Painted. This term refers to rugs that have been cosmetically “enhanced” by applying pigment or dye to the foundation of the rug after the pile is worn. It is done to cover or conceal wear and often without the buyer’s consent or knowledge.
Palmette. A flower viewed from the side.
Patched. Damaged area of a rug that has been cut out and replaced by sewing in a piece from another rug.
Pendant. A design motif found at each end of a central medallion.
Photo bleaching. This is generally a problem on wall-to-wall wool carpets in light and pastel colors. In the first six months of a new carpet, exposure to sun or UV light can result in the natural yellow color component being bleached. It is noticeable when a portion of the new carpet is uncovered after a period of time.
Pictorial. A rug woven to represent people, places and things not usually associated with oriental rug design.
Pile. The surface of a carpet formed by the cut ends of the knots that are tied onto the foundation.
Pile direction. This is the direction in which the pile naturally lies. Also known as the “nap.”
Pilling. A condition of the carpet face (which may occur from foot traffic) in which fibers become entangled with one another, forming hard masses of fibers and tangled tufts. They may be cut with scissors or electric shears.
Plied yarn. A yarn composed of two or more single yarns twisted together.
Polyester. A fiber-forming, thermo-plastic synthetic polymer. Nearly all polyester carpet is made from staple fibers, and the yarns are spun yarns. Polyester for carpet is made from terephthalic acid and ethylene glycol, and is known chemically as polyethylene terephthalate (P.E.T.).
Polypropylene. A synthetic, thermo-plastic polymer used for molded items. All polypropylene carpet fiber is solution dyed and sometimes contains ultraviolet stabilizers for outdoor use. The carpet fiber is available as both bulked continuous-filament yarns and staple for spun yarn production. Slit-film polypropylene is used in woven carpet backing. This fiber holds on to soil and tends to mat and crush.
Pooling. See “Shading.“
Prayer Rug. A small rug featuring a prayer niche (mihrab) in the field design. Inspired by the architectural features found in a mosque. The design can be curvilinear or rectilinear. Usually the rugs are no larger than 4 x 6 feet (122 cm x 183 cm).
Printed carpet. A carpet that is dyed (usually in patterns) by using either flatbed screen printing, rotary screen printing, sponge printing or what is basically a very large inkjet printer. This process is used to make inexpensive rugs often using oriental rug designs.
Rayon. A man-made fiber made from regenerated cellulose using cotton linters and wood pulp. A paste is produced that is almost pure cellulose, and extruded through a spinneret into diluted sulfuric acid which hardens the filaments. This process is known as the viscose process, thus the name viscose rayon.
Reduced. A rug that has been made smaller by trimming the sides or ends. Sections may be also be cut out across the width and/or length of the rug to be sewn back together to create a smaller rug.
Reeling. The process of unraveling continuous fiber silk cocoons.
Repair. A compromise between conservation and restoration of a rug or carpet so it becomes functional again.
Restoration. An attempt to return an object to its original or first condition. A true restoration of a rug requires the same type of fiber, yarn, dyes, and structures used in the original.
Retting. Soaking flax or hemp to separate the fiber from woody tissues by partial rotting.
Rosette. A stylized design depicting an overhead view of a flower.
Rotary Shampoo. A carpet cleaning technique in which a detergent solution is worked into the pile by a motor-driven rotating brush.
Rug. Any textile floor covering that is not wall-to-wall and fastened to the floor.
Rug Pad. A protective material under a rug that helps to minimize slippage, increase the life of the rug, make the rug feel thicker, smooth out irregularities in the floor, and absorb noise. The two main types of preferred pad (sometimes called underlayment or cushion) are synthetic felt and rubber.
Runner. A rug in which the length greatly exceeds the width. The width is usually less than 3 feet and 6 inches (107 cm).
Saph (saff). A rug containing a number of adjacent prayer niches. It is sometimes referred to as a family prayer rug.
Sculpting. In some rugs, the designs are carefully shaved around their perimeter to add a second dimension to the pile. Common in post WWII Indian, Chinese and Tibetan rugs.
Sea Grass. A fiber that comes from a plant that grows in the marshlands near the Indian Ocean with a reputation for repelling spills. It is used for wall coverings and tatami mat-type area rugs.
Seaming Tape. An adhesive tape used in the fabrication of custom rugs to bind two edges together. Also used to bind two edges of wall-to-wall carpet.
Selvage. The sides of a rug where the wefts reverse direction. The selvage may be a complex structure of multiple warps and additional wefts that are not part of the rug foundation. The selvages are usually wrapped in a separate process after the weaving is finished, called overcasting.
Semi-antique. A rugs that is 50-100 years old.
Serging. Overcasting performed by hand or machine on sides of hand-knotted and machine-made area rugs.
Shading. The pile lies in various directions over the rug and causes a difference in light reflection. This produces light and dark areas on the surface of the rug. See “Pooling.”
Shearing. The process that removes the wool from the animal to be used in rug making.
Shedding. A fuzzing effect on the rug surface caused by loose fibers. This is not a defect, but a characteristic of some rugs and carpets with loosely spun wool. The total fiber loss is relatively small and in time will gradually decrease.
Shrinkage. Results when the rug has natural fibers in the foundation or as a secondary backing, such as cotton, jute, or wool. Most rugs will have minor shrinkage (even reduction in size) when cleaned. Also see “Buckling.”
Shuttle. On a loom, a device that carries a spool of weft yarns back and forth through the warps via the shed.
Silk. The only natural filament fiber (fiber in indefinite length). One fiber will range from 300 to 1600 yards in length, Silk filaments are produced by insect larva normally referred to as “silk worms.” Silk is more expensive than other fibers and found in the face and foundation yarns of finely knotted oriental rugs. Types of silk are Cultivated (silk) and Uncultivated (wild silk).
Sisal. The fiber is derived from the sword shaped leaves of the agave plant. The fiber produced is yellow-white in color, strong and lustrous. Sisal has exceptional abrasion resistance and elasticity.
Skein. A loose coil of yarn held on a reel.
Skein dyeing. This is the process of dyeing rugs in the yarn stage; the yarn is gathered onto individual skeins (yard holders) and dyed. The yarn then is re-wound onto yarn cones or yarn beams, and the rug is either woven or tufted. Also called hank dying.
Soiling. This is the buildup of particles of soil and similar materials that cling to carpet fibers. Thorough vacuuming and proper routine cleaning will minimize this problem.
Solution dyed. Yarn that is dyed in conjunction with being extruded, as opposed to yarn dyed.
Soumak. A type of stitch that is used to describe a flat-woven or pileless rug in which the pattern-forming face yarns pass over either two or four warps and return in the opposite direction under one or two warps. This method often leaves loose threads on the back where the colors change.
Spandrel. Designs inside the borders covering the corners of the field.
Spinning. A term for both yarn and fiber production. To the synthetic fiber manufacturer, spinning is synonymous with extrusion of polymer throughout the small holes of the spinneret. To the conventional textile yarn mill, spinning is the conversion of staple fiber into spun yarn.
S-plied. Multiple yarns plied in a clockwise direction. Most yarns used in oriental rugs are Z-spun and S-plied.
Spots. Foreign material (soil, liquids, etc.) that can be removed by standard cleaning methods.
Sprouting. The condition whereby small tufts of yarn appear above the level of the rest of the rug.
Stain. Foreign material (soil, liquids, etc.) that can not be removed by standard cleaning methods.
Staple. Short lengths of fiber that may be converted into spun yarns by textile yarn spinning processes. The fibers are usually 6 – 8 inches (15 cm – 20 cm) in length and are then spun into yarn via carding, drafting and finally, spinning.
Stencil marks. On hand-tufted or needlepoint rugs, the design will often be drawn on the foundation cloth. The stencil then can bleed to the surface when wet cleaned.
Stuffer. A foundation yarn in woven carpet. Stuffers are normally large warp yarns (lengthwise yarns) that increase weight, strength, hand, stiffness and stability.
Symmetric knot. The pile yarn is looped around two adjacent warp threads and then brought up between the two. Also called Turkish or Ghiordes knot.
Synthetic dyes. These dyes were first developed by the English chemist Williams Perkin in 1856 with the color mauvine. Today most synthetic dyes are referred to as chromes. Chromes have potassium dichromate as a mordant. As opposed to natural dyes they are uniform and unyielding to the effects of time and sunlight, as they do not mellow or age.
Synthetic fibers. As the name implies, the fibers are a result of a chemical synthesis of two or more chemicals. Most synthetic fiber are derived from combining by-products of the petroleum or natural gas industries. Synthetics are classified as thermal plastic resins.
Tapestry weave. A term used for a variety of weft-faced flatweave rugs.
Tassels. Several yarns bundled together in the form of a bush. Tassels are common in tribal weavings as decorative accents on utilitarian pieces and on the sides of rugs.
Tea wash (herbal wash or antique look). Rugs treated with tea, herbs, or a variety of chemicals or synthetic dyes to give a warm, antique or yellow appearance. Cleaning or spotting, particularly with acid pH products, can remove or change the treatment.
Top. The last end of the rug to be woven. The top of the rug is the “light” end.
Tree of Life. A design featuring a large tree that divides the length of the field of the rug in half.
Tuft. An individual yarn (either cut or one half of a loop).
Tufting (hand tufting). A process by which the pattern-forming pile yarns are inserted mechanically into the foundation of the rug or with the use of a hand-held machine. These rugs can have a cut or loop pile and a heavily latexed secondary and primary back. These rugs are produced in China, India, U.S. and other countries.
Turkish knot. See “Symmetric knot.”
Turkibaff. A rug made with Turkish knots.
Urine stains. Urine contamination from an animal may cause color run, odor and/or damage to the structure and face yarns of a rug.
Ushak. (Oushak) A town in western Turkey that has produced rugs since the 15th century.
UV Fading. Sunlight and ultraviolet rays will permanently affect the color of the face fibers with prolonged exposure.
Velvet. The velvet weave is usually used to produce extremely dense plush velvet piles. It is a simple weave and is produced in solid colors of a Wilton construction.
Village rugs. Rugs woven on vertical looms without the use of a cartoon. Not so formal and rigid as workshop rugs.
Viscose. Refers to cellulose after treatment with caustic soda and bi-sulfide. Another type of rayon, which is made chiefly from wood pulp.
Volatile organic compound (VOC). Organic minerals, especially gases that evaporate into the air.
V’Soske, Inc. A New York based company that designs and produces high-end custom tufted rugs.
Warp. The foundation yarns of a rug that is strung from the top to the bottom of a loom. In oriental rugs, the knots are tied to the warp yarns, which also form the fringes at the ends of the finished rug.
Watermarking. See “shading.”
Weft. The foundation yarns of a rug that is woven across the width of a loom. The yarns are passed through alternate warp yarns after each row of knots. They serve to secure the knots in place, form part of the sides (selvages) of the rug and give the rug dimensional stability.
White knots. Areas of the rug where the warp cords have been spliced together while still on the loom. As the rug wears, they show through the pile of the rug as a small white knot.
Wires. Component of a carpet weaving loom on which the pile tufts are formed. Round wires produce loop pile carpets, and flat wires with sharp blades produce cut-pile (plush) textures.
Wool. A protein fiber grown on the skin of sheep. The use of wool for rugs goes back to over 2000 B.C. and is considered to be the oldest and finest face fiber.
WoolSafe. Established in 1991 as a testing and certification program for manufacturers of carpet cleaning chemicals.
Workshop rugs. Hand-knotted rugs woven for the commercial market factories. Most designs are curvilinear.
Woven carpet. Is produced on a loom through a weaving process by which the lengthwise yarns and widthwise yarns are interlaced to form the fabric.
Yarn. A single or multiple ply of combed or corded filaments that have been open or twisted to form a continuous strand.
Yellowing. A discoloration of a rug caused by urine, browning, spills, oxidation, water marks, etc. Correction will depend on the cause of the yellowing.
Zel-i-Sultan. A repeating design made up of small vases and flowers.
Z-spun. Yarn spun in a counter-clock-wise direction. Most yarns used in oriental rugs are Z-spun and S-plied.