Umlaut (noun)

1. A diacritical mark (¨) placed over a vowel in Germanic languages, indicating a change in sound, typically a fronting or raising of the vowel.
2. A diacritic mark (¨) that is placed over a vowel in some languages (such as German) to indicate a change in sound.

Origin:

Mid 19th century: from german umlaut, literally "change in sound", from um- "around" + laut "sound".

Examples:

1. In German, the umlaut changes the sound of the vowel in a word.
2. The umlaut over the "a" changes its sound from "ah" to "eh".
3. The umlaut is used to indicate a change in sound in Germanic languages.
4. The umlaut is used to indicate a fronting or raising of the vowel.
5. The umlaut is a diacritical mark placed over a vowel.