what’s the difference between a barn owl and a normal owl?

Question: what's the difference between a barn owl and a normal owl?
- Keywords:
  barn owl,
  owl
Asked by hannahannah to Common Crane, Barn Owl on 12 Dec 2017.
- Common Crane answered on 12 Dec 2017:
  
  Barn owls are into nuclear physics xD
  On a serious note, and maybe Barn Owl can correct me, the most common (normal) owls are barn owls.

Question: what's the difference between a barn owl and a normal owl?