Definition of "reaction" []

  • A response to a stimulus. (noun)
  • The state resulting from such a response. (noun)
  • A reverse or opposing action. (noun)
  • A tendency to revert to a former state. (noun)
  • Opposition to progress or liberalism; extreme conservatism. (noun)
  • A response to some foregoing action or stimulus (noun)

American Heritage(R) Dictionary of the English Language, Fifth Edition. Copyright (c) 2011 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

  • The reciprocal action of two things acting together (noun)
  • Opposition to change, esp political change, or a desire to return to a former condition or system (noun)
  • A response indicating a person's feelings or emotional attitude (noun)
  • Any effect produced by the action of a drug, esp an adverse effect (noun)
  • Any effect produced by a substance (allergen) to which a person is allergic (noun)
  • The simultaneous equal and opposite force that acts on a body whenever it exerts a force on another body (noun)
  • A sharp fall in price interrupting a general rise (noun) (c) HarperCollins Publishers Ltd 2016

Use "reaction" in a sentence
  • "Such a reaction is called a _reversible reaction_."
  • "So the first answer to your question is that there is no chain reaction in Earth’s core because there probably isn’t enough uranium there to initiate a chain reaction¢’‚¬?"
  • "Of particular note was the elimination of the word reaction from the diagnostic labels."