redundantyoudaoicibaDictYouDict[redundant 词源字典]
redundant: [17] Etymologically, something that is redundant ‘overflows’ because there is too much of it. The word comes from the present participle of Latin redundāre ‘flow back, overflow’ (source also of English redound [14]). This was a compound verb formed from the prefix re- ‘back, again’ and undāre ‘rise in waves, surge’, a derivative of unda ‘wave’ (source of English undulate).
=> redound, surround, undulate[redundant etymology, redundant origin, 英语词源]
redundant (adj.)youdaoicibaDictYouDict
1590s, from Latin redundantem (nominative redundans), present participle of redundare, literally "overflow, pour over; be over-full;" figuratively "be in excess," from re- "again" (see re-) + undare "rise in waves," from unda "a wave" (see water (n.1)). Of persons, in employment situations, from 1928, chiefly British. Related: Redundantly.