Denim Dictionary: N - Z



Natural dyes need help sticking to textile fibers. That help comes in two forms: mordants (used in adjective dyes) and boiling water (used in substantive dyes).
- Adjective dyes are applied when a mordant, or setting substance such as aluminum, sodium chloride, or tannic acid, combines with the dye to create an insoluble compound.
- Substantive dyes, such as indigo, involve immersing the fabric in boiling water with the dye.


These naturally-derived fibers come in two shapes and sizes: plant based and animal based.
- Plant-based fibers, such as cotton and hemp, are made of cellulose and can be used to create a wide range of fabrics, including heavy denims.
- Animal-based fibers, such as silk, wool, and cashmere, are made of protein keratin and are spun into yarn before being knitted, woven, or felted into fabric.



The most common, yet low quality, type of denim. It’s created by pressing fibers into “mock twists” to achieve a consistent yarn thickness. Though open end denim lacks the character and texture of ring-spun denim, it’s economical and sturdy and ideal for work wear.


These chemicals make your whites whiter. The fluorescent whitening agents, or optical whiteners, boost whiteness and brightness by absorbing ultraviolet (invisible) light and re-emitting it as visible light. They’re especially handy in hiding yellow coloring due to wear and tear or the manufacturing process.


Reduce your carbon footprint with organic cotton. It’s grown in toxin-free soil using growing methods that support biodiversity, prevent soil stripping, reduce the use of toxins, and minimize environmental stressors. Cotton has to meet strict regulatory growing requirements to be labelled as organic in the US.


The Italian translation of “alter fibre,” or A.F. for short. Because many fabrics include a smorgasbord of natural and synthetic fibers, this references the additional miscellaneous fibers that account for a small percentage of a fabric’s content.


Traditionally worn as work wear, overalls are a one-piece garment with a bib top and suspenders added to a pant. Overalls date back much farther than the misguided style choices of ‘90s pre-teens.

1700s: Then “slops” and considered low class, overalls were worn over pants by working men.

1850s: The garment’s color indicated the wearer’s profession: painters, white; farmers, blue; and railroad workers, pinstriped.

1950s: Rosie the Riveter—the iconic symbol for wartime working women—boosted overalls' popularity with the ladies.


This dying process is usually used on indigo or black denim to add an overtone of color by redyeing the fabric or dyeing it for a longer period of time.


The raw-denim dyeing process isn’t over until indigo comes in contact with oxygen. When dyed yarn is pulled from the dye bath and is oxidized, or exposed to the air, the dye transforms from a greenish-yellow to its true deep blue color. Oxidation also helps fix the dye color to the denim fibers.



Insoluble pigments work well for creating faded looking denim. Because pigment dye doesn’t absorb into the fibers, it's used with a resin to stick to the outside layer of the fibers. These dyes are versatile—the color palate is nearly limitless and they attach to many types of fabric.


In a word, luxurious. A slight step below Egyptian cotton, pima cotton is a high quality fabric that’s durable and absorbent due to its long fibers (1 3/8″ to 1 5/8″ in length). The fabric originated in Peru, though its namesake is the Pima Indians who cultivated the cotton in the American southwest in the early 20th century.


The number of strands, or singles, that are twisted together in a yarn. Denim is mostly woven from 2 ply (two strands) or 3 ply (three strands).


This type of denim combines cotton and polyester for strength and durability. True to its name, polycore yarn has a polyester core that is wrapped with a thin layer of cotton or polyester. Usually used on the hems and seams of jeans, polycore (or core spun) thread stands up to rough finishing treatments such as stone or river washing, and it reduces wrinkles and controls shrinkage.


All hail the world’s most popular synthetic fiber. Polyester’s selling points include its strength, luster, dye affinity, durability, and wrinkle and water resistance. The synthetic fiber was discovered in 1941, and it’s made from petroleum by-products. Today, polyester is often blended with cotton to produce denim.


This pretreatment alleviates the wear-stretch-wash-shrink cycle. Once a garment has been preshrunk, you'll notice only a small amount of shrinkage after it's washed and dried.

See also: sanforization


The strong, yet light-weight volcanic stone makes an ideal abrasion tool. Rough like sandpaper, pumice stones are used to work denim during the stone-washing process to create a worn, faded look. Rest assured, raw denim heads: your jeans have never been touched by a pumice stone.



Dry, unwashed, or raw denim is unwashed and untreated, leaving the fabric stiff with a distinctive deep blue coloring. Raw denim lets you make your own personal statement: because you break in the jeans, your movements and body shape determine how the pants crease, fade, and age.

Care: Don’t wash your raw denim for the first few months—many die-hards go six months or more—so the fabric’s natural creases and fades can fully take form. Use cold water and dark-color-friendly detergent for the inaugural wash, (we like Woolite Black) before hanging to air dry. Check out our Wear & Care Guide to make sure that your denim lives a long, beautiful life.

Historic factoid: Raw denim was the norm until the early ‘70s. To break-in and shrink their jeans faster, people would sit in a bathtub or swim in their jeans.


With its identifiable reddish tint, this type of denim has only been dyed with indigo. Unworn, this denim appears almost purple; once well-worn, it fades to a brilliant blue.


Redline is synonymous with top-grade denim. Levi’s Redline jeans are easy to spot—just look for the red line running the length of the selvedge outseam (inside the pant leg). The famous Cone Mills used color lines to distinguish fabric grades, and collectors claim that jeans made with this top-grade denim blow modern jeans out of the water.


“RHT” or “z twill” is the most widely used twill for denim, starting with Levi Strauss’ original fabric purchase. The weave’s grain line runs from the fabric’s top right-hand corner to the bottom left. In contrast with the soft nature of left-hand twill, RHT is tighter, more compact, and crisper.


Because it doesn’t hold up well under abrasion and repeated washes, this indigo-dyeing technique—usually achieved by rope dyeing—is used on jeans that are intended to fade. Ring dyeing only colors the outer layer of fibers, leaving the inside core white.


See: dual ring-spun denim


This denim uses ring-spun yarn for the warp threads. The yarn is formed by rolling and thinning fibers on repeat to create a soft, strong yarn that’s packed with character. Ring-spun yarn’s uneven texture gives denim a unique and vintage flair. Though still used for high-end and vintage jeans, ring-spun denim was widely replaced by open end denim in the late ‘70s—a less expensive and less time-intensive alternative.


Similar to stone washing, this abrasion method relies on pumice stones and cellulose enzymes to soften and age denim. Also similar to stone washing, river washing’s popularity has decreased as our collective environmental awareness has gone up; plus, it’s hard to kick the lingering bits of stone on the fabric.


Ah, our namesake. Rivets add function and flair to denim. These metal accessories date back to Nevada tailor Jacob Davis. One fateful day, while working on a pair of pants for a woodcutter, Davis had an epiphany. If rivets could strengthen horse blankets, why couldn’t they do the same for pants? He hammered a few onto the pant’s pocket corners and the rest is history.

Davis soon partnered with Levis Strauss, and the two applied for a patent for their revolutionary “improvement on fastening seams.” The patent was approved on May 20, 1873, and the blue jean was born.


Dip, oxidize, and repeat. This tried-and-true method for dyeing indigo yarn involves twisting yarn into a rope before dipping it into an indigo bath to create rope-spun yarn. Because the dye isn’t given time to fully penetrate the fibers, rope-dyed yarn fades nicely.



This yarn, which is spun counter-clockwise, is usually used to make right-handed twill.


It’s just like it sounds: guns of sand (or chemicals) are literally blasted at denim to fade the fabric. Originally done by hand and then automated, many laundry facilities have stopped sandblasting due to safety concerns for workers.


Also called emersing, this process smoothes denim to give it a worn look and feel—and helps to emphasize bodily curves. Sanding’s effects can range from the subtle to the extreme based on the length and type of sanding.


Named for the esteemed Sanford Lockwood Cluett, this process prevents shrinkage. Sanforization first promotes shrinking using water or steam, and then stretches the fabric using rubber belts and cylinders before allowing the fabric to shrink to its final size. Once sanforized, or preshrunk, the fabric will shrink very little. (Unlike unsanforized raw denim, which can shrink up to 10%.)

See also: preshrunk


Because fabric can get messy during manufacturing, it has to be processed (usually in a nice warm bath of caustic soda ash) to remove dirt and grease before it can be effectively dyed.


This premium grade cotton is right up there with Egyptian cotton. Grown in the tropical Americas, Sea Island cotton is a notch above pima cotton and is known for its soft and silky texture. All we know is, if it’s good enough for Ian Fleming’s James Bond, it’s good enough for us.


Denim’s bound, finished outseam that keeps the cut edge from unravelling. Selvedge (also called selvage or self-edge) denim is woven on an old-school shuttle loom and it’s often synonymous with high quality.

Selvedge denim can be identified at a glance by its telltale white edge running the length of the outseam, usually paired with a color. Selvedge color varies by brand: Lee uses blue or green; Wrangler’s yellow; and Levi’s red.

Note that not all raw denim is selvedge denim. Raw denim refers to how the fabric is finished/washed, while selvedge simply refers to how the denim’s edge is constructed.

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After denim has been dyed and processed, it’s grouped by color. This helps to account for the subtle variations that can creep in during the finishing process, such as minute variances in water temperature or length of dyeing. Seemingly insignificant differences can be glaring when placed side by side, so shade batching helps to ensure that only like-colored fabrics are used for a single garment.


Because simultaneously cutting multiple pieces is a skill only mastered by kindergarten teachers … the shade blanket. This mechanized cutting technique secures a stack of cloth at one end and then produces many identically-shaped pieces with one fell cut.


Because simultaneously cutting multiple pieces is a skill only mastered by kindergarten teachers … the shade blanket. This mechanized cutting technique secures a stack of cloth at one end and then produces many identically-shaped pieces with one fell cut.


This is the opening between the upper and lower warp yarns on a loom as they raise and lower during the weaving process. The weft yarns pass through the shed opening on the shuttle to finish the weaving interlace.


In weaving, the spindle-shaped shuttle carries the weft yarn back and forth through the shed opening. The flying shuttle modernized the weaving process with a lever-powered shuttle that drastically cut weaving time and increased workable fabric size.


The silhouette, or shape, of your jeans dictates how they will look on your body. (Think: bootcut vs. relaxed vs. low-rise, etc.) Factors such as tightness, inseam length, and rise all impact the silhouette.


Any rouge fibers left on the fabric at the end of garment production are removed by passing the material above a gas flame. This process, known as singeing or gassing, creates a texture that’s smooth, less prone to pilling, and ready to dye. Singeing reduces the "hairy" look that raw denim is known for.


Sizing agents such as starch and wax are applied during weaving to protect and strengthen warp yarns. Sizing is only needed during the manufacturing process, so it’s removed during the desizing process.


To counter the leg twist that can result from the shrinking process, fabric is skewed, or twisted, in the opposite direction. For example, because left-hand twill twists counterclockwise, it’s skewed clockwise. Denim is typically skewed between four and ten percent, but variables such as fabric weight, yarn twist, and twill weave all influence how much skewing a material needs.


Reassuringly less violent than its name, slasher dyeing is a form of indigo dyeing that folds sizing and dyeing into one. The process involves passing warp yarns back and forth through multiple indigo baths before sizing and winding for weaving. Slasher, or sheet, dyeing long had a bad rap because it produced a less even color than rope dyeing, but the quality is getting better with modern mechanical improvements.


Bad boy Elvis Presley first made slim fit jeans popular. This tighter fit, most noticeably through the thighs down to the leg opening, survived the rise of glam rock and metal music before becoming the unofficial uniform for hipsters and indie rock bands. Slim fit jeans defy genres in contemporary fashion, and they’re a smart addition to any wardrobe.

Style note: though “slim” is widely used interchangeably with “skinny,” the latter term favors more of the tightest fits.


These loose, continuous ropes of fiber are created during the carding process, before the fiber is spun into yarn.

Pro tip: sliver rhymes with diver, not giver.


We like to think of them as added character, not flaws. Slubs are imperfections in denim caused by uneven spinning, often on a vintage shuttle loom.


This yarn is intentionally spun with thicker sections along the yarn, or slubs, to make an irregular shape and inject added personality into the fabric. Slub (or uneven) yarn can also form intentional patterns when woven with repeating slubs—such as the crosshatch denim created by using slub yarn for both the weft and warp thread. Though it’s no longer thought of as defective, slub yarn is less durable because the inconsistencies introduce weak spots.


It’s lightweight and extremely stretchy. In fact, spandex can stretch up to 600% and still bounce back to its starting shape. The synthetic fiber was developed for Dupont by Joseph C. Shivers in the late ‘50s to replace the rubber in women’s undergarments; today it’s used in swimsuits and sportswear … and to add stretch to some jeans.

Put this in your trivia back pocket: “spandex” is an anagram for “expands.”


This age-old process involves pulling and twisting fibers to create yarn.

Way, way back in 8000 BC, spinning was done by hand with nothing more than a distaff and a spindle. The spinning wheel was introduced between 500 and 1000 AD to much fanfare, but the real revolution was James Hargreaves’ spinning jenny in 1764. The multi-spool spinning frame paved the way for machine spinning and a dramatically faster and easier process. The steps for modern spinning include carding, combing, drafting, winding, and testing. Spinning comes in all shapes and sizes, but jeans are mostly made using the ring-spun and open end methods.


This short length of fiber is used to determine fiber quality based on average length and fineness. As a general rule, the longer the staple length, the smoother the yarn and the easier the spinning. For example, luxurious Egyptian cotton measures at 35 to 60 mm while the staple length of average cotton is 26 or 27 mm.


The process of stiffening fabric using starch—whether adding it while washing or applying to dry fabric before ironing. Starching can be used to break in raw denim to keep the fabric crisp and encourage creases to set.


For this denim washing treatment, pumice stone are thrown in the wash cycle to lighten and abrade the fabric.


This popular style features a straight silhouette and even leg width from top to bottom. Because the leg width is consistent, this fit is usually more body contouring through the thigh. Sometimes mistaken for slim jeans, which taper at the bottom, straight leg jeans are classic and comfy.


This type of jean is dyed with sulfur before it's dyed with indigo. Not only does this reduce the time it takes to reach a deep color, it’s a less expensive way to produce one because it doesn't require as much indigo dye.


This dyeing method creates colors other than blue, including unique hues such as mustard and scarlet.


These jaunty accessories secure suspenders to trousers. Jeans proudly bore suspender buttons until the 1930s when they were traded out for belt loops.


These man-made organic dyes have surged in use because they’re cheaper and provide a wider color palate than natural dyes. Synthetic dye was a happy accident, discovered by a chemist trying to create the fever-quelling drug quinine from coal tar. In the denim world, most manufacturers opt for synthetic indigo.


Synthetic fibers such as polyester, spandex, and nylon are derived from coal or oil. Initially produced in the ‘30s, synthetic fibers account for half of all fiber use today in the textile industry and beyond.



Literally meaning “vertical falls,” this Japanese term references the fading that creates vertical lines in denim due to slub yarn's inconsistencies.


Each fabric finishing method, whether physical or chemical, serves a unique purpose. Textile finishing methods such as singeing, scouring, bleaching, desizing, and sanforizing all contribute to a fabric’s enhanced look, feel, or performance. As a rule, raw denim is untouched by textile finishing methods.


Straight as an arrow and widely used for hems, seams, and necklines, this matter-of-fact stitch creates a finished look. The topstitch is sewn on a garment’s right side and keeps stray layers and edges under control.


Twill is a diagonal textile weave and the name of the fabric that the weave creates. Unlike a plain weave, in which the weft thread passes across a single warp thread, the twill weave passes under two (the “twi” in “twill” means double) or more warp threads to create the fabric’s familiar diagonal ribbing. (Take a look at the inside of your denim—you should be able to see the pattern more clearly.)



See: Slub Yarn


See: Raw Denim



These authentic jeans can either be old and in their original, unworn state or old and used. Most vintage jeans are made of selvedge denim and are recognizable by the material’s irregular look.

Vintage denim is a hot commodity in today’s denim market, especially since the late ‘80s. Whether Levi’s, Lees, or Wranglers, each of the most popular vintage jean brands bear a signature look. For Levi’s, it’s the telltale red line along the selvedge, bold yellow stitching, and the big E tab.



It just doesn’t have the same ring as jeans, yet this was the pants’ name until the ‘60s. We have Jacob Davis and Levi Strauss to blame: when they introduced their first pair of riveted denim pants in 1873, they marketed them as waist overalls.


Warp yarns run vertically across the loom, and they’re carried over and under the weft yarns (which run horizontally) to hold them in place. Because the indigo-dyed warp yarns are laid across the white weft yarns, the fabric’s right side appears blue and its inside white. And, because the warp yarns take more of a beating during the weaving process, they’re made of sturdier fibers than weft yarns. In denim, the warp yarns run parallel to the outseam.


Unlike raw denim, this type of denim is washed during production after it's been dyed.


Warp and weft threads are woven together to produce a weave. Weaves come in all types, depending on the garment’s style and the number of warp and weft threads. Denim is usually woven with right hand, left hand, or broken twill.


Warp yarns run vertically; weft yarns run horizontally. The white-colored weft yarns are held in place by the warp yarns, which are carried over and under the weft. Also called filling, weft yarns can only be seen on denim’s wrong side—that’s why the inside of your blue jeans is white while the outside proudly displays the indigo-dyed warp yarns.


Denim’s grade is measured by the weight per yard of fabric, which ranges in denim from 5 to 20 ounces. Denim weight is generally divided into three categories: lightweight (12 ounces or under), midweight (12 to 16 ounces), and heavyweight (16+ ounces).


See: hige


Split into two types— and non-selvedge, or regular, denim—the width of denim is measured after the weaving process.
- Selvedge denim is woven on an old-school shuttle loom. Its width usually measures at 75 cm, and jeans made from selvedge denim bear a white, finished edge on the inner seam.
- Non-selvedge (regular) denim measures at 150 cm wide, and it’s woven on a projectile loom. Unless finished, the edge of this type of denim is prone to fraying.



Levi’s timeless 501 jeans entered the market as the XX jean. Meaning “extra, extra strong,” the XX style name speaks to the jean’s utility and working wear status. Levi’s XX were renamed 501 in 1890, but the company returned to its roots in 2009 when it brought back the XX name.



A continuous strand spun from natural or synthetic fibers that is used in knitting and weaving.


If yarn is dyed before it’s woven into cloth, it’s considered yarn dyed. Yarn dyeing’s types are hank dyeing and rope dyeing.


This is the v-shaped area at the top back of your jeans. The yoke allows the seat to curve, and the deeper the v, the bigger the curve. The size of the yoke can help hide—or emphasize—one’s backside.



In contrast to S-twist yarn, Z-twist is spun clockwise to make left-handed twill.


Pants used to button … until we got lazy and opted for the zip fly. Lee introduced the zipper in 1927, but it didn’t really take off until the 1930s when the French started raving about the zipper’s superiority to buttons. Though some pants and jeans today still feature a button fly, the zipper is more commonly used.

Fun fact: When Lee unveiled the zipper in ’27, it held a naming contest. The winner? Whizit.