Ó Sionáin
Ó SIONÁIN—I—O Sinan, Shinane, Shynane, Shinnan, Sheenan, Synan; 'descendant of Seanán' (diminutive of sean, old, wise); a variant of Ó Seanáin, which see. The Synans were once an important family in Cork and Limerick.
Alphabetical Index to Irish Surnames