Eddy
late Middle English: probably from the Germanic base of the Old English prefix ed- ‘again, back’.
wiktionary
From Middle English eddy, from Old English edēa, from ed-(“turning, back, reverse”) + ēa(“water”), equivalent to ed- + ea. [1]
etymonline
eddy (n.)
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 iþ "and, but, however"). Related: Eddies.
eddy (v.)
1730 (transitive); 1810 (intrans.), from eddy (n.). Related: Eddied; eddying.