umlaut

[oo m-lout] /ˈʊm laʊt/
noun
1.
a mark (¨) used as a diacritic 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.
Compare dieresis.
2.
Also called vowel mutation. (in Germanic languages) assimilation in which a vowel is influenced by a following vowel or semivowel.
verb (used with object)
3.
to modify by umlaut.
4.
to write an umlaut over.
Origin
1835-45; < German, equivalent to um- about (i.e., changed) + Laut sound
Examples from the web for umlaut
  • Provision is made for an umlaut and other diacritical marks, but these are dropped in common usage.
British Dictionary definitions for umlaut

umlaut

/ˈʊmlaʊt/
noun
1.
the mark (¨) placed over a vowel in some languages, such as German, indicating modification in the quality of the vowel Compare diaeresis
2.
(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
Word Origin
C19: German, from um around (in the sense of changing places) + Laut sound
Word Origin and History for umlaut
n.

1852, from German umlaut "change of sound," from um "about" (see ambi-) + laut "sound," from Old High German hlut (see listen). Coined 1774 by poet Friedrich Gottlieb Klopstock (1724-1803) but first used in its current sense 1819 by linguist Jakob Grimm (1785-1863).