eddyyoudaoicibaDictYouDict[eddy 词源字典]
eddy: [15] The ultimate source of eddy appears to be a prehistoric Germanic particle meaning ‘back, again’, represented in Old English by ed-, in Old High German by et-, and in Old Norse by ith- (it is related to Latin et ‘and’ and its various Romance descendants, such as French et and Italian ed). According to this theory, an eddy would thus be ‘water that flows back’.

What is not altogether clear, however, is precisely how that prehistoric particle became eddy. Perhaps the most likely candidate as the missing link is Old Norse itha ‘whirlpool’, but it has also been suggested that Old English may have had a word *edwǣg, whose second element, ‘wave’, would be related to English way and vogue.

[eddy etymology, eddy origin, 英语词源]
eddy (n.)youdaoicibaDictYouDict
mid-15c., Scottish ydy, possibly related to Old Norse iða "whirlpool," from Proto-Germanic *ith- "a second time, again," which is related to the common Old English prefix ed- "again, backwards; repetition, turning" (forming such words as edðingung "reconciliation," edgift "restitution," edniwian "to renew, restore," edhwierfan "to retrace one's steps," edgeong "to become young again"). Compare Old English edwielle "eddy, vortex, whirlpool." The prefix is from PIE root *eti "above, beyond" (Cognates: Latin et, Old High German et-, Gothic "and, but, however"). Related: Eddies.
eddy (v.)youdaoicibaDictYouDict
1730 (transitive); 1810 (intrans.), from eddy (n.). Related: Eddied; eddying.