Cos″tard (k?s″t?rd), n. [Prob. fr. OF. coste rib, side, F. côte, and meaning orig., a ribbed apple, from the ribs or angles on its sides. See Coast.] 1. An apple, large and round like the head.
Some consist more of air than water...; others more of water than wind, as your costards and pomewaters.
Muffett.
2. The head; — used contemptuously.
Try whether your costard or my bat be the harder.
Shak.