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noun ret·ro·ac·tion \ˌre-trō-ˈak-shən\

Definition of retroaction

  1. 1 [retroactive] :  retroactive operation (as of a law or tax)

  2. 2 [retro- + action] :  a reciprocal action :  reaction

Circa 1738

First Known Use of retroaction

circa 1738

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