WordNet (r) 3.0 (2006):

predicate calculus
    n 1: a system of symbolic logic that represents individuals and
         predicates and quantification over individuals (as well as
         the relations between propositions) [syn: predicate
         calculus, functional calculus]

The Free On-line Dictionary of Computing (30 December 2018):

predicate logic
predicate calculus

    (Or "predicate calculus") An extension of
   propositional logic with separate symbols for predicates,
   subjects, and quantifiers.

   For example, where propositional logic might assign a single
   symbol P to the proposition "All men are mortal", predicate
   logic can define the predicate M(x) which asserts that the
   subject, x, is mortal and bind x with the universal
   quantifier ("For all"):

   	All x . M(x)

   Higher-order predicate logic allows predicates to be the
   subjects of other predicates.

   (2002-05-21)