Mac Dhomhnaill
Mac DHOMHNAILL—IV—M'Coenill, M'Conill, M'Gonell, MacConell, MacConnell, MacGonnell, &c.; a variant of Mac Domhnaill, which see. This form of the surname is common in the spoken language even when the anglicised form is MacDonnell, with the radical D retained. In Co. Mayo it is sometimes pronounced Ó Comhnaill.
Alphabetical Index to Irish Surnames