mac-

1. a prefix found in many family names of Irish or Scottish Gaelic origin, as MacBride and Macdonald.

prefix

1. (in surnames of Scottish or Irish Gaelic origin) son ofMacDonald; MacNeice

common element in Scottish and Irish names, from Old Celtic *makko-s “son.” Cognate root *makwos “son” produced Old Welsh map, Welsh mab, ap “son;” also probably cognate with Old English mago “son, attendant, servant,” Old Norse mögr “son,” Gothic magus “boy, servant,” Old English mægð “maid” (see maiden).