Available Definitions:
1) n. - A substance added to an immunogenic agent to enhance the production of antibodies.
2) n. - A substance added to a formulation of a drug which enhances the effect of the active ingredient.
3) a. - Helping; helpful; assisting.
4) n. - An assistant.
5) n. - An ingredient, in a prescription, which aids or modifies the action of the principal ingredient.