A substance that is consumed in the course of a chemical reaction. It is sometimes
known, especially in the older literature, as a
reagent, but this term is better used in a more specialized sense as a test substance that
is added to a system in order to bring about a reaction or to see whether a reaction
occurs (e.g. an analytical
reagent).
Source:
PAC, 1996, 68, 149
(A glossary of terms used in chemical kinetics, including reaction dynamics (IUPAC
Recommendations 1996))
on page 183