rectangle (n.)youdaoicibaDictYouDict[rectangle 词源字典]
1570s, from Middle French rectangle (16c.) and directly from Late Latin rectangulum, from rect-, comb. form of Latin rectus "right" (see right (adj.1)) + Old French angle (see angle (n.)). Medieval Latin rectangulum meant "a triangle having a right angle."[rectangle etymology, rectangle origin, 英语词源]