[ ree-akt ]
/ riˈækt /

verb (used without object)

to act in response to an agent or influence: How did the audience react to the speech?
to act reciprocally upon each other, as two things.
to act in a reverse direction or manner, especially so as to return to a prior condition.
to act in opposition, as against some force.
to respond to a stimulus in a particular manner: reacting to a shock by jumping; to react to the word “coward” with anger.
to undergo a chemical reaction.

Origin of react

1635–45; re- + act, probably modeled on Medieval Latin reagere

Definition for react (2 of 2)

[ ree-akt ]
/ riˈækt /

verb (used with object)

to act or perform again.

Origin of re-act

First recorded in 1650–60; re- + act Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

Examples from the Web for react

British Dictionary definitions for react (1 of 2)

/ (rɪˈækt) /


(intr ; foll by to, upon etc) (of a person or thing) to act in response to another person, a stimulus, etc, or (of two people or things) to act together in a certain way
(intr foll by against) to act in an opposing or contrary manner
(intr) physics to exert an equal force in the opposite direction to an acting force
chem to undergo or cause to undergo a chemical reaction

Word Origin for react

C17: from Late Latin reagere, from re- + Latin agere to drive, do

British Dictionary definitions for react (2 of 2)

/ (riːˈækt) /


(tr) to act or perform again
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Medical definitions for react

[ rē-ăkt ]


To act in response to a stimulus.
To undergo a chemical reaction.
The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.