- a diacritic (¨) used over a vowel, as ä, ö, ü, to indicate a vowel sound different from that of the letter without the diacritic, especially as so used in German.
- (in Germanic languages) assimilation in which a vowel is influenced by a following vowel or semivowel.
- to modify by umlaut.
- to write an umlaut over.
- the mark (¨) placed over a vowel in some languages, such as German, indicating modification in the quality of the vowel
- (esp in Germanic languages) the change of a vowel within a word brought about by the assimilating influence of a vowel or semivowel in a preceding or following syllable
