Costard
/ˈkʌstəd/noun
1- Brit. a cooking apple of a large ribbed variety〈英〉（烹调用的）大苹果。
1.1
- archaic, humorous a person's head〈古, 幽默〉人头。
词源
Middle English: from Anglo-Norman French, from coste 'rib', from Latin costa.