If an acid or base is present in nearly constant concentration throughout a reaction in solution (owing to buffering or the use of a large excess), it may be found to increase the rate of that reaction and also to be consumed during the process. The acid or base is then not a @[email protected] and the phenomenon cannot be called @[email protected] according to the well-established meaning of these terms in chemical kinetics, although the @[email protected] of such a process is often intimately related to that of a catalysed reaction. It is recommended that the term [email protected]@ be used in these and analogous cases (not necessarily involving acids or bases). For example, if a @[email protected] accelerates the @[email protected] of an ester to a carboxylic acid and an alcohol, this is properly called acid @[email protected], whereas the @[email protected], by the same acid, of @[email protected] of an amide should be described as [email protected]@ by the acid: the 'acid [email protected]@' is consumed during the reaction through formation of an ammonium ion. The terms 'general acid [email protected]@' and 'general base [email protected]@' may be used as the analogues of @[email protected] and @[email protected] The term 'base-promoted', 'base-accelerated' or 'base-induced' is sometimes used for reactions that are pseudo-catalysed by bases. However, the term '@[email protected]' also has a different meaning in other chemical contexts.