Where does “Mac Dubhghaill” come from?

Mac Dubhghaill (Scottish Gaelic) comes from Scottish Gaelic Dùbh, from Old Irish dub, from Proto-Celtic dubus, from Proto-Indo-European dʰewbʰ-, from Proto-Indo-European dʰewh₂- — smoke; mist, haze.

Ancestry of “Mac Dubhghaill”, step by step

Mac Dubhghaill traces back through two separate lines of ancestry.

via Scottish Gaelic Dùbh

StepLanguageWordMeaning
1Scottish GaelicDùbhDec December
2Old Irishdubblack; morally dark, dire, gloomy, melancholy;...
3Proto-Celticdubusblack
4Proto-Indo-Europeandʰewbʰ-deep
5Proto-Indo-Europeandʰewh₂-smoke; mist, haze

via Scottish Gaelic Gall

StepLanguageWordMeaning
1Scottish GaelicGallforeigner, alien; Lowlander
2Old Irishgallforeigner; rock, pillar
3LatinGallusAlternative letter-case form of gallus; Gaul;...
4Latinpāvōpeacock, peafowl; a bird associated with Argus and sacred to Hera or Juno; eaten as a delicacy
5Ancient Greekταώςpeacock; type of fish
Every word from Proto-Indo-European dʰewh₂-Every word from Proto-Indo-European dʰewbʰ-Every word from Proto-Celtic dubus