(chemistry) Any chemical reaction in which the concentration of some component varies over time or space in a regular periodic manner.

plural of reaction

a power-generation prime mover having nozzles mounted on the moving element; turned by the reaction of the issuing fluid jet

(chemistry) any of many classes of reaction in which an atom or bond moves or migrates from a site in a reactant molecule to a different site in a product molecule

an iron-core inductor whose inductance may be changed by varying the permeability of the core; used to control large alternating currents such as in theatre light dimmers

(chemistry) Any chemical reaction initiated by the absorption of a quantum of electromagnetic radiation to form an excited state

(physics) Any nuclear reaction involving a photon and another subatomic particle

The activation of something previously inactive or inactivated.

(chemistry) A chemical reaction named after its discoverers.

(chemistry) Any vessel used to contain the reactants taking part in a reaction.