Center letter: n
Outer letter: d e o p u x
Answers (58):
  expound
  expounded
  deepen
  deepened
  denude
  denuded
  depend
  depended
  done
  donee
  donned
  dune
  dunned
  dunno
  ended
  endue
  endued
  expend
  expended
  need
  needed
  nene
  neon
  nodded
  node
  none
  noon
  nope
  noun
  nude
  odeon
  open
  opened
  oxen
  peen
  pend
  pended
  penne
  penned
  peon
  pond
  pone
  pound
  pounded
  punned
  udon
  undo
  undone
  undue
  unneeded
  unopen
  unopened
  unpen
  unpenned
  upend
  upended
  upon
  xenon