flange (n.)youdaoicibaDictYouDict[flange 词源字典]
1680s, "a widening or branching out," of unknown origin, perhaps related to Old French flanche "flank, hip, side," fem. of flanc (see flank (n.)). Meaning "projecting rim, etc., used for strength or guidance" is from 1735. As a verb from 1820.[flange etymology, flange origin, 英语词源]