四出文钱 (四出文錢) sì chū wén qián

sì chū wén qián noun coin with a square hole in the middle
Domain: History 历史 , Subdomain: China
Notes: Minted in the reign of Emperor Ling of Han 汉灵帝, with a square hole in the middle and four lines radiating out from each corner of the square, hence the name 四出文 (CC-CEDICT '四出文錢')