Center letter: r
Outer letter: d g i n o w
Answers (55):
  drowning
  wording
  wrongdoing
  donor
  door
  droid
  droning
  drown
  gird
  girding
  gorging
  gorgon
  goring
  grid
  gridiron
  grin
  grind
  grinding
  grinning
  grog
  groin
  grow
  growing
  grown
  ignoring
  indoor
  ingrown
  iron
  ironing
  ironwood
  nigiri
  noir
  nonword
  nori
  odor
  origin
  ridding
  ridging
  riding
  rigging
  rigid
  rigor
  rind
  ring
  ringing
  rondo
  rood
  rowing
  wiring
  word
  worn
  wring
  wringing
  wrong
  wronging