donkey topsail: Meaning and Definition of

don'key top"sail

Pronunciation: [key]
— Naut. Naut.
  1. a four-sided gaff topsail, used above a gaff sail or lugsail, having its head laced to a small spar.
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.