Merriam-Webster's Collegiate Dictionary
re·act
\\rē-ˈakt\\ verb ETYMOLOGY New Latin reactus, past participle of reagere, from Latin re- + agere to act — more at agent
DATE 1644
intransitive verb1. to exert a reciprocal or counteracting force or influence — often used with
on or
upon2. to change in response to a stimulus3. to act in opposition to a force or influence — usually used with
against4. to move or tend in a reverse direction5. to undergo chemical reactiontransitive verb: to cause to react
Oxford Advanced Learner's Dictionary-牛津双解-OALD7
☞ react
react / ri5Akt / verb [V]
1. ~ (to sth) (by doing sth) to change or behave in a particular way as a result of or in response to sth
起反应；(对…)作出反应；回应:
Local residents have reacted angrily to the news.
当地居民对这一消息表示愤怒。
I nudged her but she didn't react.
我用胳膊肘捅了她一下,可她没有反应。
You never know how he is going to react.
你根本不知道他会作何反应。
The market reacted by falling a further two points.
股市的反应是再下跌两个百分点。
2. to become ill / sick after eating, breathing, etc. a particular substance
(对食物等)有不良反应,过敏:
People can react badly to certain food additives.
人们对某些食品添加剂会严重过敏。
3. ~ (with sth) | ~ (together) (chemistry 化) (of substances 物质) to experience a chemical change when coming into contact with another substance
起化学反应；发生化学变化:
Iron reacts with water and air to produce rust.
铁和水及空气发生反应产生铁锈。
PHRASAL VERBS
▪ re7act a'gainst sb / sth
to show dislike or opposition in response to sth, especially by deliberately doing the opposite of what sb wants you to do
反对；反抗:
He reacted strongly against the artistic conventions of his time.
他强烈反对当时的艺术俗套。
Oxford Collocations Dictionary for Students of English
Oxford Collocations dictionary for students of Englishreact
verb
ADV. strongly | favourably, positively, sympathetically people who react positively to change | adversely, badly, negatively, unfavourably | aggressively, angrily, violently | cautiously, coolly | sharply | appropriately | immediately, instantly | quickly, swiftly The police must be able to react swiftly in an emergency. | differently | accordingly His insensitive remarks hurt and she reacted accordingly. | automatically, instinctively, spontaneously | physically
VERB + REACT tend to | be slow to The industry has been slow to react to these breakthroughs in technology. | not know how to He did not know how to react to her sudden mood swings.
PREP. against Many young people react against traditional values. | by The government reacted by increasing taxation. | to The university reacted unfavourably to the proposals. | with Her family reacted with horror when she told them.
Webster's Third New International Dictionary, Unabridged
re·act
\rē+\
verb
(
-ed/-ing/-s)
Etymology: New Latin
reactus, past participle of
reagere, from Latin
re- + agere to drive, act — more at
agent
intransitive verb1. : to exert a reciprocal or counteracting force or influence — often used with
on or
upon
< exhausting work must react on human character — Samuel Van Valkenburg & Ellsworth Huntington >2. : to respond in a particular way to a particular treatment, situation, or other stimulus
< reacted with instinctive indignation — J.P.Frank >
— often used with
to
< was not sure how the patient would react to the drug >3. : to act in opposition to some force or influence — usually used with
against
< reacted against the threat of dictatorship — New School for Social Research Bulletin >
< reacting against mass ideologies — Henry Hewes >4. : to move in or tend toward a reverse direction
: return to or toward a prior condition
< public opinion wavered briefly but soon reacted in his favor >
< stock prices reacted strongly after a brief drop >5. : to undergo chemical reaction
transitive verb: to cause to react;
specifically : to bring about a chemical reaction in
< produces ethyl chloride by reacting chlorine with waste — Lamp >Synonyms: see act
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chain-react
re-act
\(ˈ)rē+\
transitive verbEtymology: re- + act: to act or perform a second time
< in his imagination he re-acted the scene — Aldous Huxley >