Pronunciation: (ak'tu-vāt"),[key] —v.t.,-vat•ed, -vat•ing. 1. to make active; cause to function or act.
2. Physics. a. to render more reactive; excite: to activate a molecule. b. to induce radioactivity.
3. to aerate (sewage) in order to accelerate decomposition of impure organic matter by microorganisms.
4. Chem. a. to make (carbon, a catalyst, molecules, etc.) more active.
b. to hasten (reactions) by various means, as heating.
5. to place (a military unit or station) on an active status in an assigned capacity.