What is the meaning of ü?

a high front rounded vowel (IPA [y]).

an extremely short or fleeting ü.

An emoticon representing a face with a big smile.

A dictionary transcription for the GOOSE vowel

The twenty-ninth letter of the Azerbaijani alphabet, written in the Latin script.

The letter u with a trema.

The letter u with an umlaut.

The thirty-sixth letter of the Hungarian alphabet, called ü and written in the Latin script.

A letter of the Kobon alphabet.

A letter of the Southern Tutchone alphabet, written in the Latin script.

A letter of the North Frisian alphabet, written in the Latin script.

the letter u with a trema

Indicate a diaeresis in gu before i and e (e.g., paragüero, pingüino).

The twenty-sixth letter of the Turkish alphabet, called ü and written in the Latin script.

The name of the Latin-script letter Ü/ü.

The twenty-sixth letter of the Turkmen alphabet, called ü and written in the Latin script.

or

The letter U, marked for its syllabic pronunciation distinct from adjacent vowels.

Source: wiktionary.org