1. A flat pocket-sized folding case, usually made of leather, for holding paper money, cards, or photographs; a billfold. 口袋大小的平的折叠小包，常以皮革制成，用来装纸钱、卡片或像片等；钱包。
2. n. a flat pocket-sized folding case, usually made of leather, for holding paper money, cards, or photographs; a billfold. 口袋大小的、平的折叠小包，常以皮革制成，用来装纸币、卡片或相片等；钱包。
3. Opening the billfold, he carefully removed two worn pieces of notebook paper that had obviously been taped, folded and refolded many times. 他打开皮夹，小心翼翼地拿出两张用旧的笔记本纸，它们明显地被用绳子捆扎过，并且反复折叠了多次。
英英解释
n.
1. a pocket-size case for holding papers and paper money
