Buckler mustard

Buckler Buc"kler, n. [OE. bocler, OF. bocler, F. bouclier, a shield with a boss, from OF. bocle, boucle, boss. See {Buckle}, n.] 1. 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. [1913 Webster]

Note: 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. [1913 Webster]

2. (Zo["o]l.) (a) One of the large, bony, external plates found on many ganoid fishes. (b) The anterior segment of the shell of trilobites. [1913 Webster]

3. (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. [1913 Webster]

{Blind buckler} (Naut.), a solid buckler.

{Buckler mustard} (Bot.), a genus of plants ({Biscutella}) with small bright yellow flowers. The seed vessel on bursting resembles two bucklers or shields.

{Buckler thorn}, a plant with seed vessels shaped like a buckler. See {Christ's thorn}.

{Riding buckler} (Naut.), a buckler with a hole for the passage of a cable. [1913 Webster]