Alb \Alb\, n. [OE. albe, LL. alba, fr. L. albus white. Cf. Album and Aube.]

A vestment of white linen, reaching to the feet, an enveloping the person; -- in the Roman Catholic church, worn by those in holy orders when officiating at mass. It was formerly worn, at least by clerics, in daily life.

Source: Webster's Revised Unabridged Dictionary (1913)