What does the word spool mean?

Usage examples for spool

  1. Scamper and Uncle Squeaky hauled the cart with its four stout spool wheels. – Grand-Daddy Whiskers, M.D. by Nellie M. Leonard
  2. He had also provided, for some reason or other, eight small glass cups, into which he placed the legs of the two tables, and in a business- like manner he set out on the large stand a piece of white paper, a pencil, and a spool of black thread. – Sight Unseen by Mary Roberts Rinehart