Lewis & Short

effectīvus, a, um, adj. [efficio], effective, productive: causa, velut pater filii, Boëth. in Porphyr. 2, p. 58 al.
Esp. as, subst.: effectīva, ae, f. (sc. ars), practical art, productive art: sed effectivae quoque aliquid simile scriptis orationibus consequetur, Quint. 2, 18, 5.