Inspired by my current work with raw fleece, I wanted to add common fleece terms to the glossary:
Crimp: the natural bends formed along a length of fiber as it grows from a follicle in the skin. Crimp can be two-dimensional, like a wave, or three-dimensional, like adding a spiral to the wave. When a fiber is stretched, it is the crimp that allows the fiber to return to its original length, acting like a miniature spring. This quality is referred to as memory or elasticity. There is also a relationship between crimp and the softness, luster, and strength of the fiber. Generally speaking, the more crimps per inch (leaning on the Merino side of the spectrum), the finer and softer the fiber will be, while with fewer crimps per inch (leaning on the longwool side of the spectrum), the fiber will be shinier and stronger.
Grease: the natural oil in wool that is secreted by sebaceous glands in the skin. When collected & purified, it is called lanolin. Handspinners commonly call this oil "grease," while the commercial wool industry uses the term "wax" (or wool wax) to describe the exact same oils in raw wool.
Lock: a naturally occurring clump of fibers in a fleece. Some sheep breeds have very well-defined locks. Other breeds do not have defined locks, resulting in what is called an "open" fleece.
Second cuts: small pieces of wool that are the result of a shearing mistake, which are annoying to a handspinner because the pieces can form neps in yarn if they are not removed. A few second cuts are normal, but a fleece that is riddled with second cuts from sloppy shearing will lose a lot of value and sell for a cheaper price.
Skirt: the process of removing undesirable wool from a raw fleece. This would typically include wool from the belly and outer edges of the fleece, as well as any wool that is full of VM or manure. The vast majority of raw fleeces offered for sale are skirted fleeces.
Staple: synonymous with lock, referring to a group of fibers that clump together in a fleece. Staple is most often used when describing fiber length, ie. "this fleece has an average staple length of 4 inches."
Suint: basically, this is sheep sweat. Suint is the natural salt that is secreted from the skin of the animal and is is water-soluble.
Yolk: a collective term to describe the combination of both grease and suint in a raw fleece. It is becoming a more old-fashioned term, or perhaps used more in the commercial wool industry, with handspinners simply saying "grease" to describe both the natural oils & salts in a raw fleece.