\Cos"tard\ (k?s"t?rd), n. [Prob. fr. OF. coste rib,
side, F. c[^o]te, 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 [apples] 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.