Definition of "activator"

One who, or that which, activates.  examples

(chemistry) Something that activates a catalyst  examples

(biology) Any chemical or agent which regulates one or more genes by increasing the rate of transcription.

(biology) A type of effector that increases the rate of enzyme-mediated reactions.

A type of dopant used in phosphors and scintillators.  examples

(mining) An agent that enables the flotation of a mineral or minerals.  examples

(chiropractic) A hand-held device that delivers a controlled fast thrust to a joint, muscle, etc., to help stimulate nervous system activity.  examples