|Cyrillic letter Monocular O|
|The Cyrillic script|
Monocular O (majuscule, minuscule) is one of the rare glyph variants of Cyrillic letter O. This glyph variant was used in certain manuscripts in the root word (eye), and also in some other functions, for example, in the word- and syllable-initial position. It is used in some late birchbark letters of the 14th and 15th centuries, where it is usually differentiated from a regular ?, used after consonants, also by width, being a broad On (?) with a dot inside.