| Ɔ | |
| Letter: | Ɔ ɔ |
| Imagealt: | Upper and lower case Open O |
| Script: | Latin script |
| Type: | Alphabet |
| Typedesc: | ic and Logographic |
| Unicode: | U+0186, U+0254 |
| Direction: | Left-to-Right |
Open o or turned c (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.
The Yucatec Maya language used Ɔ to transcribe the alveolar ejective affricate pronounced as /[t͡sʼ]/ consonant in the orthography of the Colonial period. Now dz or tsʼ is preferred. [1]
On the macOS US Extended keyboard, ɔ and Ɔ can be typed with followed by or .
thumb|The first of these Claudian letters is the antisigma.Open o looks like a reversed letter 'C'. Claudius introduced a Ɔ (the antisigma) with the intention of replacing bs and ps.
The Scandinavian explanatory symbol (forklaringstegnet) can be typeset using the open o followed by a colon, thus: ɔ:. It is used to mean "namely", "id est", "scilicet" or similar.[4]
This letter is often used to refer to the Copyleft official sign, which looks like an open o with a circle around it.