Mainly U.S.: apparently from the vocabulary word, denoting the three in a suit of playing cards (from Old French treis, Latin tres). It may sometimes be given to a third son, but often it is regarded as no more than a variant of Troy.
Irish: 1. reduced Anglicized form of Gaelic Ó Fithcheallaigh ‘descendant of Fithcheallach ’, a byname meaning ‘chess player’. See also Mcfeeley. 2. reduced Anglicized form of Gaelic Ó Fáilbhe (see Falvey).