A meta-predicate is a predicate that calls other predicates 
dynamically, modifies a predicate, or reasons about properties of a 
predicate. Such predicates use either a compound term or a predicate 
indicator to describe the predicate they address, e.g., assert(name(jan)) 
or abolish(name/1). 
With modules, this simple schema no longer works as each module defines 
its own mapping from name+arity to predicate. This is resolved by 
wrapping the original description in a term <module>:<term>, 
e.g., assert(person:name(jan)) or
abolish(person:name/1).
Of course, when calling assert/1 
from inside a module, we expect to assert to a predicate local to this 
module. In other words, we do not wish to provide this :/2
In the example below, we use this to define maplist/3 
inside a module. The argument `2' in the meta_predicate declaration 
means that the argument is module-sensitive and refers to a predicate 
with an arity that is two more than the term that is passed in. The 
compiler only distinguishes the values 0..9 and :+-?
:- module(maplist, [maplist/3]).
:- meta_predicate maplist(2, ?, ?).
%%      maplist(:Goal, +List1, ?List2)
%
%       True if Goal can successfully be applied to all
%       successive pairs of elements from List1 and List2.
maplist(Goal, L1, L2) :-
        maplist_(L1, L2, Goal).
maplist_([], [], _).
maplist_([H0|T0], [H|T], Goal) :-
        call(Goal, H0, H),
        maplist_(T0, T, Goal).
:^+-?call(0) 
or maplist(1, +).
:consult(:).
-?**?*?+^^-annotated 
goal of
setof/3, bagof/3, aggregate/3 
and aggregate/4. 
It is processed similar to `0', but leaving the ^//Each argument that is module-sensitive (i.e., marked 0..9, :^:/2
:- meta_predicate
        meta(0, +).
meta(Module:Term, _Arg) :-
        format('Module=~w, Term = ~q~n', [Module, Term]).
?- meta(test, x). Module=user, Term = test ?- meta(m1:test, x). Module=m1, Term = test ?- m2:meta(test, x). Module=m2, Term = test ?- m1:meta(m2:test, x). Module=m2, Term = test ?- meta(m1:m2:test, x). Module=m2, Term = test ?- meta(m1:42:test, x). Module=42, Term = test
The meta_predicate/1 declaration is the portable mechanism for defining meta-predicates and replaces the old SWI-Prolog specific mechanism provided by the deprecated predicates module_transparent/1, context_module/1 and strip_module/3. See also section 6.15.