Dictionary of Medieval Names
from European Sources

Macduff m. Old Irish mac 'son' + Old Irish duib 'of [the] black'.

Scotland
Latin
1070x1093 Mackduffe (abl) ESC X; 1095 Magdufe (gen) ibid. XV
Cite as: S.L. Uckelman. "Macduff". In S.L. Uckelman, ed. The Dictionary of Medieval Names from European Sources, Edition 2016, no. 4. http://dmnes.org/2016/4/name/Macduff.