Center letter: r
Outer letter: a b d i m n
Answers (50):
  midbrain
  airman
  aria
  arid
  armada
  armband
  barb
  barbarian
  bard
  barmaid
  barman
  barn
  bird
  birdbrain
  birria
  brad
  braid
  brain
  bran
  brand
  briar
  brim
  darn
  dinar
  drab
  drain
  dram
  drama
  drib
  mandarin
  marimba
  marina
  marinara
  marm
  midair
  midrib
  minibar
  mirin
  nadir
  rabbi
  rabid
  radar
  radian
  radii
  raid
  rain
  ramada
  rand
  rani
  rind