1. an active and efficient cause; capable of producing a certain effect

- their research uncovered new disease agents

Definition categories: object, cause

2. a representative who acts on behalf of other persons or organizations

Definition categories: person, representative

3. a substance that exerts some force or effect

Definition categories: substance, cause

4. a businessman who buys or sells for another in exchange for a commission

Similar word(s): broker, factor

Definition categories: person, bourgeois, businessperson

5. any agent or representative of a federal agency or bureau

Definition categories: person, functionary, official

6. the semantic role of the animate entity that instigates or causes the happening denoted by the verb in the clause

Definition categories: communication