Found:

Meta-variable

**SEMANTICS: **an expression of a **meta language**, that can be used to refer to arbitrary object language expressions in a logical language.
** EXAMPLE:** the syntax definition of a **predicate logic** could contain
sentence (i).

(i) If phi is a formula in L, then so is Neg phiIn (i), phi is a metavariable standing for any formula of the logical language L.

LIT. | Gamut, L.T.F. (1991) |