n. (Logic) an operator containing a variable, written `(x)' or `(∀x)', that indicates that the open sentence that follows is true of every member of the relevant domain, that is, that every replacement of that variable by a name yields a true statement. For example,
(x)(Fx → Gx)
is read as for all x, if x is an F then it is a G, that is, all Fs are Gs, and is true if and only if Fa → Ga is true of every member of the domain.