  We introduce the notion of an ACP process algebra and the notion of a meadow
enriched ACP process algebra. The former notion originates from the models of
the axiom system ACP. The latter notion is a simple generalization of the
former notion to processes in which data are involved, the mathematical
structure of data being a meadow. Moreover, for all associative operators from
the signature of meadow enriched ACP process algebras that are not of an
auxiliary nature, we introduce variable-binding operators as generalizations.
These variable-binding operators, which give rise to comprehended terms, have
the property that they can always be eliminated. Thus, we obtain a process
calculus whose terms can be interpreted in all meadow enriched ACP process
algebras. Use of the variable-binding operators can have a major impact on the
size of terms.
