1. (in pharmacology) A substance added to a @D01863@ to speed or increase the action of the main component.
  2. (in immunology) A substance (such as aluminium hydroxide) or an organism (such as bovine tuberculosis bacillus) which increases the response to an @A00394@.
PAC, 1993, 65, 2003. (Glossary for chemists of terms used in toxicology (IUPAC Recommendations 1993)) on page 2010 [Terms] [Paper]