a person or thing that .
Chemistry, Biochemistry. a catalyst.
any impurity in a mineral that causes luminescence.
Compare (def 3).
Orthodontics. a removable appliance, usually of hard plastic, that is worn in the mouth instead of a fixed appliance to help align the teeth and improve the relationship of the lower jaw to the upper.
The Black Doctor closed his eyes wearily and flipped an activator switch.
Contamination Crew Alan Edward Nourse
They may have been, and the use of the activator may have been extorted from one of them.
Temple Trouble Henry Beam Piper
Finally, he poked the activator bar, and watched as the machine spat out tape.
The Players Everett B. Cole
Nargyll wants to move your ship into one of the sheds, but the activator key’s gone.
Astounding Stories, June, 1931 Various
activator ac·ti·va·tor (āk’tə-vā’tər)
An agent that renders another substance active or accelerates a process or reaction.
The fragment produced by chemical cleavage of a proactivator that induces the enzymatic activity of another substance.
engaged in ; characterized by energetic work, participation, etc.; busy: an active life. being in a state of existence, progress, or motion: active hostilities. involving physical effort and : active sports. having the power of quick motion; nimble: active as a gazelle. characterized by , motion, volume, use, participation, etc.: an active market in wheat; […]
- Active anaphylaxis
active anaphylaxis active anaphylaxis ac·tive anaphylaxis (āk’tĭv) n. The anaphylactic response produced in an individual following inoculation with an antigen to which the person is sensitized.
- Active barrier
noun a movable object that prevents passage of certain entities but allows passage of predefined entities, esp. a security barricade Examples A sliding gate is an active barrier; a retaining wall is a passive barrier.
- Active centre
noun (biochem) the region in an enzyme molecule in which the reactive groups that participate in its action are juxtaposed Also called active site Historical Examples Wallingford, six miles above Streatley, is a very ancient town, and has been an active centre for the making of English history. Three Men in a Boat Jerome K. […]