From the Irish surname, Gaelic Ó Riain ‘descendant of Rian’. Ryan is associated with the film actor Ryan O'Neal (b. 1941) and is one of several names of Celtic origin that have become very popular throughout the English-speaking world since the 1990s. It is also now well established in North America as a girl's name.
Portuguese: religious byname from Portuguese nascimento ‘birth’, ‘nativity’ (Late Latin nascimentum, from nasci ‘to be born’). This was one of the epithets of the Virgin Mary (Maria do Nascimento), and was also used as a given name for children born at Christmas.