1. [ noun ] a response that reveals a person's feelings or attitude

"he was pleased by the audience's reaction to his performance" "John feared his mother's reaction when she saw the broken lamp"

Related terms: response react
2. [ noun ] (biology) a bodily process occurring due to the effect of some foregoing stimulus or agent
Synonyms: response

"a bad reaction to the medicine" "his responses have slowed with age"

Related terms: bodily_process reflex passage learned_reaction rebound tropism immune_response automatism taxis transfusion_reaction electrical_skin_response answer kinesis overreaction double_take react
3. [ noun ] an idea evoked by some experience

"his reaction to the news was to start planning what to do"

Related terms: idea
4. [ noun ] (chemistry) a process in which one or more substances are changed into others
Synonyms: chemical_reaction

"there was a chemical reaction of the lime with the ground water"

Related terms: chemical_process oxidation neutralisation reduction decomposition chemical_equilibrium chain_reaction photochemical_reaction endothermic_reaction elimination_reaction displacement double_decomposition exothermic_reaction oxidation-reduction saponification aldol_reaction addition_reaction hydrolysis chemistry
5. [ noun ] doing something in opposition to another way of doing it that you don't like

"his style of painting was a reaction against cubism"

Related terms: resistance backlash
6. [ noun ] (politics) extreme conservatism in political or social matters

"the forces of reaction carried the election"

Related terms: conservatism
7. [ noun ] (mechanics) the equal and opposite force that is produced when any force is applied to a body

"every action has an equal and opposite reaction"

Related terms: force mechanics
Similar spelling:   reactionist