The Bayer designation Omicron Canis Majoris (ο CMa / ο Canis Majoris) is shared by two stars, in the constellation Canis Major:
They are separated by 2.06° on the sky.
ο¹ Canis Majoris was member of asterism 軍市 (Jūn Shì), Market for Soldiers, Well mansion. ο² Canis Majoris was not any member of asterism.
References
Omicron Canis Majoris Wikipedia(Text) CC BY-SA