Other forms: reagents
A reagent is a substance used to create a chemical reaction. Reagents cause transformations.
Chemists love reagents because they cause chemical reactions. For example, a certain type of reagent could tell a chemist if something contains a poison. Like a reactant or a catalyst, a reagent makes something happen. It can help you remember reagents are active if you remember that other agents — like secret agents — are also active and make things happen.