The Collaborative International Dictionary of English v.0.48:
Barn \Barn\ (b[aum]rn), n. [OE. bern, AS. berern, bern; bere
barley + ern, [ae]rn, a close place. [root]92. See Barley.]
A covered building used chiefly for storing grain, hay, and
other productions of a farm. In the United States a part of
the barn is often used for stables.
Barn owl (Zool.), an owl of Europe and America (Aluco
flammeus, or Strix flammea), which frequents barns and
Barn swallow (Zool.), the common American swallow (Hirundo
horreorum), which attaches its nest of mud to the beams
and rafters of barns.