react

To act in response.

Noun

An emoji used to express a reaction to a post on social media.
- Sad reacts only

From re- + act. Piecewise doublet of redact.

To act in response.
- How did she react to the news?
Synonyms: take
To act or perform a second time; to do over again; to reenact.
- It is somewhat extraordinary, that the offence for which James II, was expelled, that of setting up power by assumption, should be re-acted, under another shape and form, by the parliament that expelled him. - 1791,...
To return an impulse or impression; to resist the action of another body by an opposite force
- Every body reacts on the body that impels it from its natural state.
To act upon each other; to exercise a reciprocal or a reverse effect, as two or more chemical agents; to act in opposition.
To cause chemical agents to react; to cause one chemical agent to react with another.
To post a reaction (icon or emoji indicating how one feels about a posted message).