← Dictionary

reaction

/riˈæk.ʃən/
IELTSAcademic
noun
  1. 1.

    A reaction is something you do, say, or feel in response to an event, person, or situation. It can be a physical, emotional, or spoken response.

    • Her reaction was immediate.
    • I had no reaction at all.
    • What was his reaction to the news?
  2. 2.

    In science, a reaction is a change or process caused by mixing substances or by an action on the body.

    • The chemicals caused a strong reaction.
    • This medicine may cause allergic reactions.
    • The reaction happened quickly.

Adinary Nuance

Reaction is a broad word for a response to something. It is more general than response, which often sounds more neutral and formal. Reaction can also suggest a sudden or emotional reply, especially in speech and news writing. Use response when you want to sound calmer or more measured.

In other languages

Vietnamese
phản ứng
Spanish
reacción
Chinese
反应
Japanese
反応
Korean
반응

Etymology

Reaction came into English in the 1600s from French réaction, based on Latin re- meaning 'back' and actio meaning 'a doing'. It first meant an action in return, then a response.

Common phrases

reaction tostrong reactionpublic reactionchemical reaction

Synonyms

Related words

Frequently asked questions

What is the difference between reaction and response?
Reaction is often more immediate and emotional. Response can sound more neutral and thoughtful.
Is reaction used in science?
Yes. In science, it often means a change caused by mixing substances or by contact.
Can I say 'my reaction was good'?
Yes, but it sounds more natural to say 'my reaction was positive' or 'I reacted well'.
Is reaction a formal word?
It is common in both speaking and writing, including academic and business English.