Gael, Or Gail (Gaelic, Gaedhil, Gadhel, or Gaoidheal), the plural of Gal or Cal (akin to Latin celo, to hide, as the people dwelt or were hidden in forests; or more probably signifying wanderer), the name of the northern and western branch of the great Celtic family of nations, whose other branch is formed by the Kymri or Cymri. The Gael inhabit the Scotch highlands and Ireland, and distinguish themselves as Gael Albinach, or Gael of Albion, and Gael Erin-nach, or Gael of Erin (from ar or iar, west, and ie, island; Romanized into Ierne and Hibernia). Both these divisions are called Erse, the former by the Scotch lowlanders, who derive them from Ireland. The descendants of the Kymri dwelling in Wales are called Gwyddel by the Gael, while those in France are named Breiziz (Britons); and those of Cornwall {corn, cairn, rock, and gal) ceased in the 18th century to speak their peculiar dialect. Gaedhilic or Gaoid-hilg is the epithet especially appropriated to the Irish and to their tongue, and Gaelic especially denotes both the highland Scotch and their language.

Caledonia is composed of Cal and dun or don, mountain; Gaeldoch of Gael and dock, land; both being names of Scotland; but Gaolldoch or strangers' land is the distinctive name of that part of Scotland which is inhabited by non-Celtic people. (See Celts, and Celts, Languages and Literature of the.)