Fòram na Gàidhlig

Just from curiosity: if 'mac' means 'son' (a boy by definition), why do you need to add 'gille' ?

This is precisely what I'm talking about
So MhicGilleDhuibh would be an equivalent for the surname Black? Like in Meall Lochan Mhic Gille Dhuibh?
Can you tell me what the three words (Mhic Gille Dhuibh) mean in Gaelic?

I've noticed that there are Gaelic equivalents for some English names so I was wondering if this can apply to Scottish surnames as well.

Thank you for a thorough explanation
The Black Water reservoir/lake that I have in mind, however, is a made-up place.
What I'm looking for is just a straightforward tr*nsl*t**n of that name to Gaelic, given that Black is a surname - not the colour (I'm not sure if it makes a difference?).

Marta

Hello everyone :) I am writing a story in which some places need to have Gaelic names and I was wondering if you could help me with tr*nsl*t**n. The place I'm having a bit of a trouble with is a reservoir called 'Black Water' (Black is a family name in this case). How should it be called in Gaelic? ...