foolscap (n.)youdaoicibaDictYouDict[foolscap 词源字典]
also fool's-cap, 1630s, "type of cap worn by a jester;" see fool (n.1) + cap (n.). From c. 1700 as a type of writing paper, so called because it originally was watermarked with a jester's cap.[foolscap etymology, foolscap origin, 英语词源]