ˈkästə(r)d, ˈkȯs-; Brit usually ˈkəs- noun
( -s )
Etymology: Middle English, perhaps from Old French coste rib + Middle English -ard; from its ribbed appearance — more at coast
1. : any of several large oval strongly ribbed English cooking apples — compare codling , pippin
2. archaic : pate
whether your costard or my ballow be the harder — Shakespeare