Etymology
* As an English surname, from Middle English Devennport, named after the River Dane + port. The first element is from Welsh dafn (“trickle, drop”), ultimately from Proto-Indo-European *dʰewh₂- (“mist, haze”).
* As an Irish surname, from Ó Donndubhartaigh (“descendant of Donndubhartach”), which is from donn (“brown”) + dubh (“black”) + artach (“nobleman”); see airigh.