Source : Webster's Revised Unabridged Dictionary (1913)

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 : WordNet®

alb
     n : a white linen liturgical vestment with sleeves; worn by
         priests