Found:

Atomic formula

SEMANTICS: a formula without connectives or quantifiers, made up only of a predicate with arguments, like P(a) or R(x,y). More complicated formulas like [P(a) & R(x,y)] or All(x)[P(x)] are not atomic formulas due to the presence of & and All.

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