Ɔ

Open o (majuscule: Ɔ, minuscule: ɔ) is a letter of the extended Latin alphabet. In the International Phonetic Alphabet, it represents the open-mid back rounded vowel. It is used in the orthographies of many African languages using the African reference alphabet.

On the Mac OS U.S. Extended keyboard, ɔ and Ɔ can be typed with ⌥ Option+: followed by c or C.