A baptismal name for a boy
Onesius
One saint bore this name
Saints named Onesius
Questions
The name day of Onesius is March 5, the feast of Martyr Onesius of Isauria.
The Sinaxarion archive holds 1 saints named Onesius, with their lives and icons.
Yes. Onesius is the name of a saint of the Orthodox Church, so the child will have Martyr Onesius of Isauria as patron.