buckler

American Heritage® Dictionary of the English Language, Fourth Edition

1. n. A small, round shield either carried or worn on the arm.
2. n. A means of protection; a defense: "has enjoyed a reputation as a shield and buckler for . . . the academic avant-garde” ( Donal Henahan).
3. v. To shield; protect.

Century Dictionary and Cyclopedia

1. n. A shield; specifically, a small shield intended to parry blows or thrusts, but not so large as to cover the body. The buckler of the middle ages in western Europe was generally round, and rarely more than two feet in diameter, eighteen inches, or even less, being a more common size. It was generally grasped by the hand only, and held at arm's-length, and in combat was interposed to receive the blow of a sword, like the dagger which was held for this purpose in the left hand in later times. See shield.
2. n. Nautical, a piece of wood fitted to stop the hawse-holes of a ship, to prevent the sea from coming in, or to stop the circular hole in a port-lid when the gun is run in. Hawse-bucklers are now made of iron.
3. n. The anterior segment of the carapace or shell of a trilobite.
4. n. A plate on the body or head of a fish; especially, a plate in front of the dorsal fin in various catfishes, or Nematognathi.
5. n. A stage of the molting American blue crab, Callinectes hastatus, when the shell has become nearly hard.
6. n. A piece of beef cut off from the sirloin.
7. To be a buckler or shield to; support; defend.

Wiktionary

1. 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. In the sword and buckler play of the Middle Ages in England, the buckler was a small shield, used, not to cover the body, but to stop or parry blows.
2. n. obsolete A shield resembling the Roman scutum. In modern usage, a smaller variety of shield is usually implied by this term.
3. n. zoology One of the large, bony, external plates found on many ganoid fishes.
4. n. zoology The anterior segment of the shell of trilobites.
5. n. nautical 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.
6. v. obsolete To shield; to defend.

GNU Webster's 1913

1. 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.
2. n. One of the large, bony, external plates found on many ganoid fishes.
3. n. The anterior segment of the shell of trilobites.
4. n. (Naut.) 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.
5. v. obsolete To shield; to defend.

WordNet 3.0

1. n. armor carried on the arm to intercept blows