Church Slavonic printed fonts and Slavonic manuscripts
Historical typefaces (like poluustav (semi-uncial), a standard font style for the Church Slavonic typography) and old manuscripts represent several additional glyph variants of Cyrillic O, both for decorative and orthographic (sometimes also "hieroglyphic") purposes, namely:
broad variant (?/?), used mostly as a word initial letter (see Broad On for more details);
narrow variant, being used now in Synodal Church Slavonic editions as the first element of digraph Oy/oy (see Uk (Cyrillic) for more details), and in the editions of Old Believers for unstressed "o" as well;
variant with a cross inside (Crossed O), ?, used in certain manuscripts as the initial letter of words ? 'around, nearby' (the root of this Slavonic word, , means 'cross') and 'district, neighbourhood' with their derivatives;
"eyed" variant (Monocular O) with a dot inside (?/?), used in certain manuscripts in spelling of word 'eye' and its derivatives. In many other texts, including the birchbark letters, the monocular O was not used as a hieroglyph but largely as a synonym of Broad On signalling the word-initial position;
"two-eyed" variants (Binocular O) with two dots inside (?/? or ?/?), also double "O" without dots inside were used in certain manuscripts in spelling of dual/plural forms of the words with the same root 'eye';
"many-eyed" variant (Multiocular O), ?, used in certain manuscripts in spelling of the same root when embedded into word 'many-eyed' (an attribute of seraphs).
In Russian, O is used word-initially, after another vowel, and after non-palatalized consonants. Because of a vowel reduction processes, the Russian /o/ phoneme may have a number of pronunciations in unstressed syllables, including [?] and [?].
In Macedonian the letter represents the sound /?/.