Irish : variant of Dermond, a reduced Anglicized form of
Gaelic Ó Duibhdhiorma ‘descendant of Duibhdhiorma’ a
personal name meaning ‘black trooper’ (see Dormer 3). There has
been some confusion between the personal names Duibhdhiorma and
Diarmaid, so that Dearmond alternates with
McDermott.