The close back unrounded vowel, or high back unrounded vowel, is a type of vowel sound used in some spoken languages. Acoustically it is a close back-central unrounded vowel.[1] The symbol in the International Phonetic Alphabet that represents this sound is ⟨ɯ⟩. Typographically a turned letter m, given its relation to the sound represented by the letter u it can be considered a u with an extra "bowl". It is not to be confused with ⟨uɪ⟩, a sequence of the symbols ⟨u⟩ and ⟨ɪ⟩ (which represent the close back rounded vowel and the near-close front unrounded vowel, respectively), nor with ⟨ω⟩, which is an unofficial symbol for the near-close back unrounded vowel.