Rhawlaw, in the Welsh, signifies a lieutenant, a vicar; and Rheoli, to govern, to rule. It may be local, from Ral, Raoul or Ralph, and leigh, or ley, a field or place.

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

RALEIGH. An ancient Devonshire family, who, according to Fuller, derived their name from "a well-known town" in that county. I cannot discover any town, or even village, so called, though the name is indissolubly connected with the shire, in the persons of the two famous Raleighs ■ — -William, Bishop of Winchester, temp. Henry III., and the renowned, but unfortunate, Sir Walter, who were both born ■within its limits. In the Rotuli Hundredorum for the county of Somerset, there is a Warinus de Raleghe.

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