Originally an Anglicized form of the ancient Irish male name Ceallach. It is now very widely used in the English-speaking world, mainly as a girl's name. This is a transferred use of the surname Ó Ceallaigh ‘descendant of Ceallach’.
English: status name from Middle English gode ‘good’ + man ‘man’, in part from use as a term for the master of a household. In Scotland the term denoted a landowner who held his land not directly from the crown but from a feudal vassal of the king.