noun
- a person or thing that activates.
- Chemistry, Biochemistry. a catalyst.
- any impurity in a mineral that causes luminescence.Compare inhibitor(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.
n.
- 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.