activator

noun

1. a person or thing that activates.
2. Chemistry, Biochemistry. a catalyst.
3. any impurity in a mineral that causes luminescence.Compare inhibitor(def 3).
4. 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.

1. An agent that renders another substance active or accelerates a process or reaction.
2. The fragment produced by chemical cleavage of a proactivator that induces the enzymatic activity of another substance.