资料来源 : Webster's Revised Unabridged Dictionary (1913)

Birrus \Bir"rus\, n. [LL., fr. L. birrus a kind of cloak. See
   {Berretta}.]
   A coarse kind of thick woolen cloth, worn by the poor in the
   Middle Ages; also, a woolen cap or hood worn over the
   shoulders or over the head.