ipse dixitip·se dix·it
Origin of ipse dixitL, he himself has said (it)
Origin of ipse dixitFrom Latin ipse d&imacron;xit, he himself said (it) : ipse, he himself + d&imacron;xit, third person sing. perfect tense of d&imacron;cere, to say.
From Latin ipse (“himself”) dīxit (“he said”), third-person singular perfect active of dīcō (“say, speak”), meaning "he himself said it", a calque of Ancient Greek αὐτός (autos) ἔφα (epha). Originally used by the followers of Pythagoreanism, who claimed this or that proposition to be uttered by Pythagoras himself.
ipse dixit - Legal Definition