- apex (n.)
[apex 词源字典]
- c. 1600, from Latin apex "summit, peak, tip, top, extreme end;" probably related to apere "to fasten, fix," hence "the tip of anything" (one of the meanings in Latin was "small rod at the top of the flamen's cap"), from PIE *ap- "to take, reach." Proper plural is apices.[apex etymology, apex origin, 英语词源]