(1):
(n.) One of the large, bony, external plates found on many ganoid fishes.
(2):
(n.) A block of wood or plate of iron made to fit a hawse hole, or the circular opening in a half-port, to prevent water from entering when the vessel pitches.
(3):
(n.) The anterior segment of the shell of trilobites.
(4):
(v. t.) To shield; to defend.
(5):
(n.) A kind of shield, of various shapes and sizes, worn on one of the arms (usually the left) for protecting the front of the body.