1. A substance that renders another substance, or catalyst, active, or that accelerates a process or reaction.
2. The fragment, produced by chemical cleavage of a proactivator, that induces the enzymic activity of another substance.
3. An apparatus for making substances radioactive; e.g., neutron generator, cyclotron.
4. A removable type of myofunctional orthodontic appliance that acts as a passive transmitter of force, produced by the function of the activated muscles, to the teeth and alveolar process that are in contact with it.
catabolite gene activator
plasminogen activator
polyclonal activator
tissue plasminogen activator