When these fibers are twisted together (spun), it is called yarn. It is strong, durable, and resists rotting in damp climates. It is one of the few textiles that has a greater breaking strength wet than dry. It has a relatively long "staple" (individual strand length) relative to cotton and other natural fibers.
The standard measure of bulk linen yarn is the lea. A yarn having a size of 1 lea will give 300 yards per pound. The fine yarns used in handkerchiefs, etc. might be 40 lea, and give 40x300 = 1200 yards per pound.
Up until the 1950's or so the finest linen yarn was made in Scotland, Ireland, and Belgium. The climates of these locations were ideal for natural processing methods called "retting". As years went by many of the finest factories in those areas closed, and most linen is currently made in China.
The decrease in use of linen may be attributed to the increasing quality of synthetic fibers, and a decreasing appreciation of buyers for very high quality yarn and fabric. Very little top-quality linen is produced now, and most is used in low volume applications like hand weaving and as an art material.
The characteristic most often associated with linen yarn is the presence of "slubs", or small knots that occur randomly along its length. However, these are actually defects associated with low quality. The finest linen has a very consistent diameter with no slubs.
Linen is also used for cloth, canvases, sails, tents, and paper. Due to its one-time common use to make fine fabric, "linens" became the generic term for sheets and pillowcases, although these are now often made of cotton or synthetic fibers.
Due to its strength, in the middle ages linen was used for shields and gambesons, but also for underwear and other clothings.
Linen is available in different qualities variing from almost silk-like to sack-linen. Linen is usually white to ivory, may be washed at 95°C, should be ironed when damp.
When being washed the first time, linen shrinks a lot.
In addition, the term in English, flaxen-haired, denoting a very light, bright blonde, comes from a comparison to the color of raw flax fiber.