It is used in some late birchbark letters of the 14th and 15th centuries, where it is usually differentiated from a regular о, used after consonants, also by width, being a broad On (ѻ) with a dot inside.

[3] A similar jocular glyph (called "double-dot wide O") has been suggested as a phonetic symbol for the "nasal-ingressive velar trill", a paralinguistic impression of a snort, due to the graphic resemblance to a pig snout.

Multiocular O (ꙮ) is a unique glyph variant found in a single 15th-century manuscript, in the Old Church Slavonic phrase "серафими многоꙮчитїй" (abbreviated "мн҇оꙮчитїй"; serafimi mnogoočitii, 'many-eyed seraphim').

It was documented by Yefim Karsky in 1928 in a copy of the Book of Psalms from around 1429,[5][6] now found in the collection of the Trinity Lavra of St.

After a 2022 proposal to change the character to reflect this, it was updated later that year for Unicode 15.0 to have ten eyes and to extend below the baseline.

The crossed O is primarily used in the word ꚛкрест (around, in the region of) in early Slavonic manuscripts,[14] whose component крест means 'cross'.

In its alphabet (in primers and grammar books), broad and regular shapes of О share the same position, as they are not considered different letters.