M' i.e. Mac. A Gaelic prefix meaning son. (Gothic, magus, a son; Sanskrit, mah, to grow; Welsh, magu,
to breed.) The Welsh ap is Mac changed to Map, and contracted into 'ap or 'p, as Apadam ('Ap Adam),
Prichard ('P Richard).

Persons of Scottish ancestry dislike having their "Mac" changed to "Mc".