Pima Cotton Glossary

The terms used to describe cotton are precise, and most marketing uses them loosely. This page defines what each one means, with a link to the guide where it is explained in full.

Extra-long staple (ELS)

The industry classification for the longest grades of cotton fiber. It is a measurement, not a marketing term. What is Pima cotton?

Staple length

The average length of the individual fibers in a sample of cotton, measured in millimetres and recorded on the HVI report for a bale. Pima commonly exceeds 34 mm; Upland cotton runs roughly 22 to 28 mm.

Gossypium barbadense

The botanical species to which Pima cotton belongs. Supima and most Egyptian cotton are the same species. Pima vs. Supima vs. Egyptian cotton

Upland cotton

Gossypium hirsutum, the species that accounts for the large majority of world cotton production and the cotton in most T-shirts. Shorter staple than barbadense.

HVI

High Volume Instrument testing. The standard laboratory measurement applied to a bale of cotton, reporting staple length, micronaire, strength and uniformity. It is the document that turns a claim about fiber into a measurement.

Micronaire

A measure of fiber fineness and maturity, reported on the HVI. Finer fibers allow finer yarn, within limits — a micronaire that is too low indicates immature fiber that dyes unevenly.

Carding

The step that untangles raw cotton fibers and aligns them into a loose rope called a sliver. Every cotton yarn is carded. Carding does not sort by length. Combed vs. carded cotton

Combing

The step after carding that removes the shortest fibers before spinning. It is the mechanical reason a fabric does or does not pill, and it costs real weight: the short fraction is discarded. What combing removes, and why

Yarn count

A measure of yarn fineness, written as a ratio such as 30/1 or 40/1. A higher first number means a finer yarn. Finer yarn spins more slowly, which is part of why Pima fabric costs more. Why is Pima cotton more expensive?

GSM

Grams per square metre: the weight of a fabric. A lightweight T-shirt jersey commonly falls between 140 and 180 GSM. Measured under ASTM D3776.

Pilling

A tangle of fiber ends that have worked loose from the yarn and knotted at the fabric surface. It is mechanical, caused by friction, and it is reduced — not eliminated — by longer and combed fiber.

Hand

How a fabric reads to the touch. It comes down to how many fiber ends reach the surface and how much friction they create, which is decided during spinning rather than finishing.

Yarn-forward

A rule of origin used in United States trade agreements: the yarn and every subsequent stage must occur within the partner countries for a garment to qualify. It is what the fabric affidavit certifies. Where our fabric comes from

Supima

A registered trademark of the association representing United States growers of Pima cotton, licensed to mills and brands. A contraction of "Superior Pima." It is a certification mark, not a different fiber.

OEKO-TEX

A testing and certification system that screens textiles for harmful substances. Certificates belong to the mill that holds them and are specific to named articles, with an expiry date.

Short bath ratio

A dyeing method that uses a lower volume of water per batch than conventional equipment. A description of process, not an environmental claim.

How we decide what to publish, and what we have not measured: our editorial standards.