Definition from Wiktionary, the free dictionary
adjuvant (plural adjuvants)
- A thing which aids or assists; an auxiliary.
- One who helps or facilitates; an assistant.
- (medicine) An additive (as in a drug) that aids or modifies the action of the principal ingredient.
- (medicine) Something (as in a method) that enhances the effectiveness of a medical treatment.
- (immunology) A substance enhancing the immune response to an antigen.
- Helping; helpful; assisting.
Related terms 
- adjuvant in Webster’s Revised Unabridged Dictionary, G. & C. Merriam, 1913
- adjuvant in The Century Dictionary, The Century Co., New York, 1911
- adjuvant at OneLook Dictionary Search
- third-person plural present active indicative of adjuvō