Spend enough time exploring the world of premium denim and you'll quickly discover that it has a language all of its own.
From slub and nep to selvedge and sashiko, denim enthusiasts often throw around terms that can seem confusing to newcomers.
At Jeanstore, we're passionate about helping people understand not only the brands they wear but also the fabrics, construction methods and details that make exceptional garments so special. Whether you're investing in your first pair of Japanese jeans or simply curious about the terminology used throughout the denim world, this guide breaks down some of the most common terms you're likely to encounter.
Selvedge
Perhaps the most well-known term in premium denim, selvedge (or self-edge) refers to denim woven on traditional shuttle looms. These looms produce fabric with a tightly finished edge that prevents fraying, eliminating the need for overlocked seams.
Selvedge denim is often identified by the coloured line visible along the outseam when jeans are cuffed, traditionally red but sometimes available in other colours depending on the mill or brand. While selvedge doesn't automatically guarantee quality, it is often associated with slower production methods, greater attention to detail and more characterful fabrics.
Slub/Slubby
Slub refers to the irregular thickness of yarn used during the weaving process. Rather than appearing perfectly smooth, slubby denim contains thicker and thinner sections throughout the fabric.
This uneven texture creates visual depth and often leads to highly distinctive fading patterns as the denim ages. The more pronounced the slub, the more textured and dynamic the fabric tends to appear.
Nep/Neppy
Nep describes the small flecks or speckles that appear within a fabric. These tiny knots of fibre create a slightly fuzzy, textured surface and are particularly common in vintage-inspired Japanese denim.
Nep can give fabric a rougher, more organic appearance that closely resembles workwear fabrics produced during the early twentieth century. Many enthusiasts appreciate nep because it adds character and individuality to a garment.
Wabash
Wabash fabric originated in American railroad workwear during the late nineteenth and early twentieth centuries. It is typically recognised by its distinctive dotted stripe pattern running vertically through the fabric.
Historically, the dots were created through a discharge printing process that removed indigo dye to reveal the lighter pattern underneath. Today, Wabash remains a favourite among heritage workwear brands and is commonly seen on shirts, jackets and work trousers.
Sashiko
Sashiko is a traditional Japanese stitching technique that was originally developed as a method of reinforcing and repairing garments. The name translates roughly as "little stabs", referring to the small running stitches used throughout the fabric.
Modern sashiko fabrics often replicate the appearance of these stitched patterns through specialised weaving techniques. The resulting material is durable, heavily textured and visually distinctive, making it a popular choice for jackets, overshirts and workwear-inspired garments.
Herringbone Twill
Named after the skeletal pattern of a herring fish, herringbone twill features a distinctive zigzag weave that differs from standard denim construction.
The weave creates subtle visual texture while maintaining excellent durability. Herringbone fabrics have long been associated with military clothing, workwear and heritage garments.
Duck Canvas
Despite the name, duck canvas has nothing to do with ducks. The word comes from the Dutch term doek, meaning cloth.
Duck canvas is a tightly woven cotton fabric known for its durability and resistance to wear. Brands often use it for work jackets, chore coats, utility trousers and bags where toughness is a priority.
Chambray
Chambray is often mistaken for denim due to its similar appearance. However, the two fabrics are constructed differently.
While denim uses a twill weave, chambray is woven using a plain weave with coloured warp yarns and white weft yarns. The result is a lighter, softer fabric that retains the classic blue workwear aesthetic while being ideal for shirts and warm-weather garments.
Indigo
Indigo is the iconic blue dye most closely associated with denim. Traditional indigo dyeing coats the outer layer of the yarn while leaving the core relatively untouched.
As garments are worn, the surface dye gradually wears away, creating the unique fades and patina that denim enthusiasts value so highly. This process is one of the defining characteristics of raw denim.
Raw Denim
Raw denim refers to denim that has not been washed or treated after leaving the loom. Unlike pre-washed jeans found on many high street shelves, raw denim arrives stiff, dark and untouched.
Over time, the fabric softens and develops personalised fading patterns based entirely on the wearer's lifestyle and habits, creating a truly unique garment.
One Wash
One wash denim has undergone a single rinse after production. This process removes some shrinkage while retaining much of the texture, colour and character associated with raw denim.
Many people view one wash denim as a practical middle ground between completely raw denim and heavily processed jeans.
Rope Dyeing
Rope dyeing is the traditional method used to colour denim yarns with indigo. Large bundles of yarn are repeatedly dipped into indigo dye baths and exposed to air between each dip.
This technique creates the characteristic white core that allows denim to fade so beautifully over time.
Loopwheel
Although not strictly a denim term, loopwheel frequently appears in discussions surrounding premium Japanese clothing.
Loopwheel machines slowly knit fabric without placing tension on the yarn. The resulting material is exceptionally soft, durable and comfortable, making it highly sought after for sweatshirts, hoodies and T-shirts.
Patina
Patina refers to the visual character that develops on a garment through regular wear and ageing.
In denim, patina includes fading, creasing, whiskers, honeycombs and all the subtle signs of use that make a garment uniquely yours. Unlike wear and tear, patina is often celebrated as a mark of authenticity.
Understanding the jargon
Many of these terms describe techniques and materials that originated decades, and sometimes centuries, ago. Understanding them helps explain why certain garments feel different, fade differently or command a higher price than mass-produced alternatives.
More importantly, these details tell the story behind the fabric. Whether it's a heavily slubbed Japanese selvedge denim, a vintage-inspired Wabash work shirt or a textured sashiko jacket, every term reflects a particular tradition, technique or approach to craftsmanship.