Reaction etymology

English

English word reaction comes from Latin re-, Latin agendum, and later Latin reactio ((physics, chemistry) reaction.)

Etymology of reaction

Detailed word origin of reaction

Dictionary entry Language Definition
re- Latin (lat) Again; prefix added to various words to indicate an action being done again, or like the other usages indicated above under English.. Back, backwards.
agendum Latin (lat)
reago Latin (lat)
reactio Latin (lat) (physics, chemistry) reaction.
reaction Old French (842-ca. 1400) (fro)
reaction English (en) (chemistry) A transformation in which one or more substances is converted into another by combination or decomposition. An action or statement in response to a stimulus or other event.