Mac Oscair
Mac OSCAIR—IV—M'Cosquyr, M'Cowsker, M'Kuesker, MacOscar, MacUsker, MacCosker, MacCusker, MacKusker, MacKuscar, (Cosgrove, Cosgrave); 'son of Oscar' (a Teutonic personal name, found in Domesday Book in the time of Edward the Confessor, or it may be from oscar, a combatant, champion); an Ulster surname.
Alphabetical Index to Irish Surnames