react
re·act / rēˈakt/ • v. [intr.] respond or behave in a particular way in response to something: Iraq reacted angrily to Jordan's shift in policy the market reacted by falling a further 3.1%. ∎ (react against) respond with hostility, opposition, or a contrary course of action to: they reacted against the elite art music of their time. ∎ (of a person) suffer from adverse physiological effects after ingesting, breathing, or touching a substance: many babies react to soy-based formulas. ∎ Chem. & Physics interact and undergo a chemical or physical change: the sulfur in the coal reacts with the limestone during combustion. ∎ [tr.] Chem. cause (a substance) to undergo such a change by interacting with another substance. ∎ Stock Market (of stock prices) fall or rise in reaction to events, developments, etc.