Center letter: b
Outer letter: i n o r w a
Answers (40):
  rainbow
  arbor
  arborio
  baba
  baboon
  banana
  baobab
  barb
  barbarian
  barn
  baron
  barrio
  barrow
  birria
  boar
  boba
  bobbin
  bonbon
  bonobo
  boob
  booboo
  boon
  boor
  born
  boron
  borrow
  bowwow
  brain
  bran
  brawn
  briar
  brio
  brow
  brown
  inborn
  nabob
  noob
  rabbi
  ribbon
  robin