compound/1 meta-logicalcompound(+Term)
Term is currently instantiated to a compound term.
| ?- compound(9).
no
| ?- compound(a(1,2,3)).
yes
| ?- compound("a").
yes
| ?- compound([1,2]).
yes
atom/1,
atomic/1,
number/1,
var/1,
callable/1,
nonvar/1,
simple/1