MAC, a prefix held, in modern Gaelic, to signify son, as Macdonald, son of Donald, MacFarlane, son of Farlane, &c. Under the head of CAMPBELL, instances are given where it cannot have implied originally son, but rather great, a corruption from the Latin magnus. In the similar Italian names in Mag and Mac, as Magliola, Macciavelli, and the Dutch and Portuguese Magallaen or de Magallaens, it also appears to signify great. Macallane is the Gaelic pronunciation of MacLean; and allane was, till the Reformation, a frequent form, in Scottish speech, for alienus, a foreigner. There is a passage in Gildas, in which this prefix, as given to Maglocune, originally a monk, afterwards a Pictish king in Wales, first appears in history; the reproaches addressed to whom, as is the manner of this satirist, consist of ironical play upon his corrupt Latin name of great placeholder, he having been nephew of the former king; such as being great in stature of body as in kingdom or station, &c. It was probably also originally territorial, with the same meaning, in some instances, as Macnab of Macnab, or of that ilk. In this view it becomes descriptive, as names not hereditary are; and it occurs long prior to the use of surnames or hereditary names in Scotland.