As described in historical dictionaries

An Etymological Dictionary of Family and Christian Names (1857)

(origin: Celtic and Gaelic. Local) From Ath, a ford, and dare, from darach, the place of oaks, "The ford of the oaks." There is the following tradition of the origin of this surname: "Thomas, the sixth Earl of Desmond, while on a hunting excursion was benighted, and lost his way, between Tralee and Newcastle, in the county of Limerick, where he was received and hospitably entertained by one William McCormic, whose daughter he subsequently married. At this alliance, the family and clan took umbrage. Resigning his title and estate to his youngest brother, he fled to France in 1418, and died of grief at Rouen, two years afterward. The King of England attended his funeral. He had issue, Maurice and John; Robert, the son of Maurice, returning to Ireland, with the hope of regaining the estates and title of Thomas, his ancestor, slew Gerald, the White Knight, in single combat at Athdare, the ford of the oaks, whence he received the name of Adaire. He embarked for Scotland, where he married Arabella, daughter of John Campbell, Lord of Argyle."

Arthur, William (1857) An Etymological Dictionary of Family and Christian Names. New York: Sheldon, Blakeman. Public Domain.


Patronymica Britannica (1860)

ADAIR. A branch of the great AngloHibernian family of Fitz-Gerald settled at Adare, a village in co. Limerick, aud thus acquired the local surname. In the XV.

Lower, Mark A (1860) Patronymica Britannica: a dictionary of the family names of the United Kingdom. London: J.R. Smith. Public Domain.


Origin: Celtic

Region of origin: British Isles

Country of origin: Ireland

Religion of origin: Christian

Language of origin: Gaelic

BritishSurnames.uk is a Good Stuff website.