Center letter: o
Outer letter: r a b c d k
Answers (57):
  backboard
  backdoor
  corkboard
  aboard
  abroad
  accord
  adobo
  arbor
  arco
  ardor
  baobab
  barbacoa
  boar
  board
  boba
  bock
  boob
  booboo
  book
  bookrack
  boor
  broad
  brood
  brook
  cacao
  cardboard
  carob
  cobra
  coca
  cock
  cocoa
  coda
  cook
  cookbook
  cord
  cork
  croak
  croc
  crock
  crook
  dock
  dodo
  doodad
  door
  dorado
  dork
  kabob
  kook
  odor
  okra
  orca
  road
  roar
  rock
  rococo
  rood
  rook