activator Definition

to make active or more active: such as

to make (something, such as a molecule) reactive or more reactive

to convert (something, such as a provitamin) into a biologically active derivative

a clot-dissolving enzyme with an affinity for fibrin that is produced naturally in blood vessel linings and is used in a genetically engineered form to prevent damage to heart muscle following a heart attack and reduce neurological damage following ischemic stroke —abbreviation TPA