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.

accession accessory accompaniment addenda addendum additament addition additive additory additum adjunct alterative analeptic ancillary annex annexation appanage appendage appendant appurtenance appurtenant assistant assisting attachment augment augmentation auxiliary carminative coda collateral complement concomitant continuation contributory corollary corrective counterirritant curative emmenagogue expectorant extension extrapolation fixture fostering healing helping hormone iatric increase increment instrumental maturative medicative medicinal ministerial ministering ministrant nurtural nutricial offshoot pendant reinforcement remedial restorative sanative sanatory serving side effect side issue subservient subsidiary supplement synergistic tailpiece therapeutic theriac undergirding vasodilator vitamin