Толковый словарь английского языка - umlaut

I. noun Etymology: German, from umaround, transforming + Laut sound Date: circa 1845 1. the change of a vowel (as ü to ē in goose, geese) that is caused by partial assimilation to a succeeding sound or that occurs as a reflex of the former presence of a succeeding sound which has been lost or altered, a vowel resulting from such partial assimilation, a diacritical mark ¨ placed over a vowel to indicate a more central or front articulation, II. transitive verb Date: 1879 to produce by ~, to write or print an ~ over