Ó Deagánaigh, Dean, Deane, Deen
The surname Dean is of Anglo-Saxon origin. It is originally derived from the Old English word "denu" (Middle English, "dene") meaning "valley." Another common variant of this surname is Deane and Deen. Dean is also an anglisized form of the Gaelic surname Ó Deagánaigh and Ó Duibhne.