If you buy apparel long enough, you will sit in a meeting where someone says "180 GSM single jersey, ring-spun, compacted" and everyone nods. Half the room knows what that means. This page is for the other half.
These are the terms that come up most often, and what each one actually tells you about a garment.
Weight and measurement
GSM
Grams per square metre — the standard way to express fabric weight. It is the single most useful number for comparing two fabrics. Rough orientation for cotton jersey: around 140–160 GSM is light and drapey, 170–200 is standard T-shirt weight, 220 and up is heavy and structured. Wovens use the same unit but sit in different ranges, so only compare GSM within the same construction.
oz/yd²
Ounces per square yard — the US equivalent of GSM. Roughly, 1 oz/yd² is about 34 GSM. You will see this in American spec sheets and on some denim.
Knit constructions
Single jersey
The basic T-shirt knit. One set of needles, a smooth face, a slightly looped back. Thin, stretchy, drapey, and cheap to produce. Most retail tees are single jersey.
Interlock
Two interlocking sets of stitches, giving a smooth face on both sides. Denser, more stable and less prone to curling than single jersey. Often used for higher-end tees and polo bodies.
Rib
A knit with raised vertical lines, made to stretch and recover. Used almost everywhere for neckbands and cuffs, because it holds its shape after being pulled over a head.
French terry
Looped on the inside, smooth on the outside. The standard sweatshirt and hoodie fabric. Heavier than jersey — commonly 240–300 GSM.
Fleece
Brushed on the inside for softness and warmth. Warmer and bulkier than French terry, and more prone to pilling over time.
Woven constructions
Poplin
A plain weave with fine crosswise ribs. Smooth, crisp and relatively light — the classic shirting fabric.
Twill
A diagonal weave. Denser and more durable than plain weave, with a visible diagonal line. Used for chinos, workwear and heavier shirts.
Yarn terms
Ring-spun
Yarn made by twisting fibres in a ring frame. Smoother, stronger and softer than the alternative, and more expensive. One of the main reasons two 180 GSM jerseys feel different.
Open-end (rotor)
A faster, cheaper spinning method. Slightly rougher hand and more prone to pilling than ring-spun, though perfectly serviceable for many products.
Combed vs carded
Combed cotton has had short fibres removed, leaving a smoother, stronger yarn. Carded cotton retains them, giving a rougher hand and more pilling over time.
Yarn count
How fine the yarn is. In cotton, a higher single number means a finer yarn — 30s is finer than 20s. Finer yarn generally feels softer but can be less durable.
Stretch and stability
Elastane (spandex)
A fibre blended in — usually 3–5% — to give the fabric recovery: the ability to spring back after stretching. Without it, a neckline stretched over a head stays stretched. It also changes how fabric behaves under heat, which matters for rhinestones and heat transfers.
Mechanical stretch
Stretch that comes from the knit structure rather than a fibre. Recovers reasonably, but can relax with wear.
Tubular vs open-width
Tubular fabric is knitted as a tube and used as-is. Open-width is slit and processed flat. The difference affects side seams, shrinkage behaviour and how the fabric is cut.
Pre-shrunk / compacted
Fabric that has been shrunk at the mill before cutting, so the finished garment shrinks less after washing. Costs more, behaves better. Always ask whether the fabric is compacted and what the residual shrinkage is.
Hand feel
Hand
The overall feel of a fabric — softness, weight, drape, surface. Not a single measurable property, but the result of yarn type, knit density, weight and finishing. When a buyer says "I want it to feel like this sample", hand is what they mean.
Finishing
Any treatment applied after knitting or weaving: washing, brushing, enzyme treatment, softeners, calendering. Finishing is often what separates a basic fabric from a premium one at the same weight — and it is usually the first thing cut when a schedule tightens.
What to do with these terms
Use them in your specification. "180 GSM" alone is not enough — composition, construction, yarn type and finishing all change the garment. Written together, they describe a fabric. Separately, they describe a category.
If you want the longer version — how to choose between these options, and how to write them into an order — see how to choose fabric for custom apparel. And if a supplier changes the fabric after you approve it, this is what happened and how to prevent it.
The short version
GSM tells you weight. Construction tells you behaviour. Yarn type and finishing tell you quality. Composition tells you everything else.
If a supplier can explain all four about the fabric they are quoting, you are talking to someone who knows their product. If they can only give you a GSM number, ask the other three questions.
Questions about a specific fabric? Write to lemon@mtdmj.com — we have been making garments in Guangzhou since 2003 and we will tell you what is realistic at your volume. The questions buyers ask most are on our FAQ page.
MTDMJ (Senhean Garment Co., Ltd.) is a custom apparel manufacturer in Guangzhou, China. We have been making garments since 2003 — twenty-three years and more than 900 clients later, in our own factory, with our own sample room, cutting room and export team. We work on a quote basis, with a minimum of 100 pieces per style and 30/70 payment terms.
Keep the conversation going. We share sourcing notes, factory-floor detail and buyer guides on LinkedIn, Facebook and Medium. If you're planning an order, write to lemon@mtdmj.com.
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