n. In philology, the German name, invented by Grimm, for a vowel-change in the Germanic languages, brought about by the influence of a vowel in the succeeding syllable: namely, of the vowel i, modifying the preceding vowel in the direction of e or i, and of the vowel u, modifying the preceding vowel toward a or u.In philology, to form with the umlaut, as a form; also, to affect or modify by umlaut, as a sound.