Transferred use of the surname, in origin a patronymic from Will. Use as a given name in the United States was inspired by President (Thomas) Woodrow Wilson (1856–1924); compare the similar adoption as a given name of Woodrow.
Altered spelling of Irish O’Halvey. In Counties Galway and Mayo this is an Anglicized form of Gaelic Ó hAilmhic ‘descendant of Ailmhac’, a personal name meaning ‘noble son’. In Leinster, Halvey is found as an equivalent of Holloway.