Save Type Surname (from nickname) Usage Irish (Anglicized, Modern) Pronounced Pron. SLAT-tree, SLAT-tə-ree, SLAT-ter-ee [key] Meaning & History Irish (Munster): reduced form of O’Slattery, an Anglicized form of Gaelic Ó Slat(ar)ra ‘descendant of Slatra’, a byname meaning "robust", "strong", "bold".