Center letter: i
Outer letter: a d l n o v
Answers (45):
  nonvalid
  vindaloo
  aioli
  anion
  anvil
  avail
  avian
  avid
  avoid
  dial
  dildo
  dill
  dino
  diva
  divan
  idol
  inlaid
  inland
  invalid
  laid
  lain
  lanai
  lanolin
  lion
  livid
  loin
  naiad
  nail
  nonillion
  olio
  onion
  ovoid
  vain
  valid
  vanilla
  vanillin
  vial
  villa
  villain
  viol
  viola
  violin
  vivid
  void
  voila