Broad On
Broad On (Ѻ, ѻ), or Round Omega, is a letter of the Cyrillic script. It is a Cyrillic O variant. It is used in Church Slavonic. It sounds like [ō]. It stands for 70.
Broad On Media
St. Olga icon at St Volodymyr's Cathedral, Kyiv. The letter can be seen in the inscription above her left shoulder.