Meaning of mast clamp

mast' clamp"

Pronunciation: [key]
  1. a pierced slab of hardwood built into the deck structure of a small ship or boat to receive the force of the mast, which is fitted tightly through it.
  2. Also calleda metal collar fitted to a thwart of a small boat to steady a mast.
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.