| verb | put in motion or move to act “trigger a reaction” |
| verb | make active or more active “activate an old file” |
| verb | make more adsorptive “activate a metal” |
| verb | aerate (sewage) so as to favor the growth of organisms that decompose organic matter |
| verb | make (substances) radioactive |
| adjective | (of sewage) treated with aeration and bacteria to aid decomposition |
| adjective | (of e.g. a molecule) made reactive or more reactive |
| adjective | rendered active; e.g. rendered radioactive or luminescent or photosensitive or conductive |
| adjective | (military) set up and placed on active assignment “a newly activated unit” |
| trip | noun | a catch mechanism that acts as a switch |
| tripper | noun | a catch mechanism that acts as a switch |
| actuator | noun | a mechanism that puts something into automatic action |
| act | noun | something that people do or cause to happen |
| actuation | noun | the act of propelling |
| trigger | noun | an act that sets in motion some course of events |
| activation | noun | stimulation of activity in an organism or chemical |
| spark | noun | a small but noticeable trace of some quality that might become stronger |
| activator | noun | (biology) any agency bringing about activation; a molecule that increases the activity of an enzyme or a protein that increases the production of a gene product in DNA transcription |
| air | noun | a mixture of gases (especially oxygen) required for breathing; the stuff that the wind consists of |
| aerator | noun | an apparatus for exposing something to the air (as sewage) |