The term "Blair" is the genitive
of a gaelic word, "Blar" meaning field or battle field.
It is used widely for both places and surnames, one of the earliest
known for the former being the Barony of Blair in Ayrshire granted
by King William in the mid-12th century.
While the name has been spelled 16 different ways, only 3 survive
today: Blair, McBlair, Bleher.