v. t. To make active. [ Obs. ] [ 1913 Webster ]

adj. 1. (Sewage treatment) treated with aeration and bacteria to aid decomposition; -- of sewage [ WordNet 1.5 ]

3. (Physics) made reactive or more reactive; -- of e.g. a molecule
Syn. -- activated, excited [ WordNet 1.5 ]

4. rendered active; -- as e.g. radioactive or luminescent or photosensitive or conductive
Syn. -- activated [ WordNet 1.5 ]

5. (Military) set up and placed on active assignment a newly activated unit
Syn. -- activated [ WordNet 1.5 ]

adj. prenom. 1. causing motion or action or change
Syn. -- actuating(prenominal) [ WordNet 1.5 ]

n. 1. same as activation{ 1 }.
Syn. -- energizing, activation [ WordNet 1.5 ]

n. 1. the process of making active.
Syn. -- energizing, activating [ WordNet 1.5 2. making active and effective (as a bomb). [ 1913 Webster ]

certain devices, as bombs or artillery shells, are designed to be unable to operate until a specific action (activation or arming) is taken to make them operable. [ WordNet 1.5 ]

n. 1. any agency bringing about activation; (Biol.) a molecule that increases the activity of an enzyme or a protein that increases the production of a gene product in DNA transcription. [ WordNet 1.5 ]