Costard
/ˈkɒstəd
/ /ˈkʌstəd/noun
1British A cooking apple of a large ribbed variety.The cooking equivalent was the Costard, which gave rise to the term costermonger, first applied to apple salesmen.
2 archaic, humorous A person’s head.
Origin
Middle English: from Anglo-Norman French, from coste 'rib', from Latin costa.