About the Macmillan surname
The surname Macmillan is associated with a patronymic formation. The Mac-/Mc- formation is traditionally patronymic and means “son of” in Gaelic languages. The surname may originally have expressed descent before becoming fixed as a hereditary family name. Different families could independently adopt a surname formed from the same given name.
Pronunciation:
Mak-mi-jan/makmijɑ̃/