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 "and, but, however"). Related: Eddies.

eddy (v.)

1730 (transitive); 1810 (intrans.), from eddy (n.). Related: Eddied; eddying.

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Definitions of eddy from WordNet
eddy (v.)
flow in a circular current, of liquids;
Synonyms: purl / whirlpool / swirl / whirl
eddy (n.)
a miniature whirlpool or whirlwind resulting when the current of a fluid doubles back on itself;
Synonyms: twist
Eddy (n.)
founder of Christian Science in 1866 (1821-1910);
Synonyms: Mary Baker Eddy / Mary Morse Baker Eddy