barn owl

American Heritage® Dictionary of the English Language, Fourth Edition

1. n. A predatory nocturnal bird (Tyto alba) having a white, heart-shaped face, buff-brown upper plumage, and pale underparts, often nesting in barns and other buildings. Also called monkey-faced owl.

Century Dictionary and Cyclopedia

1. n. The common white owl, Strix flammea or Aluco flammeus: so called from being often found in barns, where it is useful as a destroyer of mice. Its conspecies or varieties inhabit nearly all temperate regions of the globe. The variety found in the United States is Aluco pratincola. Also called church-owl.
2. n. plural The owls of the barn-owl type, genera Strix or Aluco and Phodilus, which differ so decidedly from all other owls that naturalists now consider them types of a distinct family. See owl and Aluconidæ.

Wiktionary

1. n. An owl of the genus Tyto, often having a white face and commonly found in barns and other farm buildings.

GNU Webster's 1913

1. n. (Zoöl.) an owl of Europe and America (Aluco flammeus, or Strix flammea), which frequents barns and other buildings.

WordNet 3.0

1. n. mottled buff and white owl often inhabiting barns and other structures; important in rodent control