protuberance (n.)youdaoicibaDictYouDict[protuberance 词源字典]
1640s, from Late Latin protuberantem (nominative protuberans), present participle of protuberare "to swell, bulge, grow forth," from Latin pro- "forward" (see pro-) + tuber "lump, swelling" (see tuber).[protuberance etymology, protuberance origin, 英语词源]