What is "mcdonnell"

MacDonnell, Macdonnell, or McDonnell is a surname of Scottish and Irish origin. It is an anglicized form of the Gaelic name "Mac Domhnaill", which means son of Donald (Angicized version of the Scottish Gaelic Dòmhnall and Irish Domhnall). The name Donald or Domhnall is ultimately derived from the Proto-Celtic word elements dubno ("world") and val ("rule").The name is a variant other Clan Donald surnames such as Macdonald, McConnell and Donaldson.