What is a single strand of fiber known as?

A single strand of fiber is known as a filament because it refers specifically to a long and thin structure that can be woven or twisted together with others to create various textile products. In the context of fiber and textiles, the term "filament" is used to describe the smallest unit of a fiber, making it fundamental in the production of threads and yarns.

Yarn generally consists of multiple filaments twisted together, which gives it strength and thickness. Thread is a finer type of yarn, typically used for sewing, and also consists of twisted fibers. Cord, on the other hand, refers to thicker strands that can be made from several fibers twisted or braided together, and is used in a variety of applications where strength is required, such as in rope or string. Therefore, while yarn, thread, and cord all involve the use of fibers, it is the filament that specifically denotes a single strand of fiber, distinguishing it from these other related terms.