(chemistry) a process in which one or more substances are changed into others; there was a chemical reaction of the lime with the ground water

[ Syn: chemical reaction ]

an idea evoked by some experience; his reaction to the news was to start planning what to do'

a bodily process occurring due to the effect of some antecedent stimulus or agent; a bad reaction to the medicine; his responses have slowed with age

[ Syn: response ]

(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'

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'

extreme conservatism in political or social matters; the forces of reaction carried the election'

doing something in opposition to another way of doing it that you don't like; his style of painting was a reaction against cubism'