noun

1. A single elongated piece of a given material, roughly round in cross-section, often twisted with other fibers to form thread.

   “The microscope showed a single blue fiber stuck to the sole of the shoe.”

2. A material in the form of fibers.

   “The cloth is made from strange, somewhat rough fiber.”

3. A material whose length is at least 1000 times its width.

   “Please use polyester fiber for this shirt.”