Center letter: a
Outer letter: c d i t u v
Answers (23):
  viaduct
  acacia
  acai
  acid
  acidic
  addict
  adduct
  attic
  audit
  avid
  cacti
  cava
  cicada
  data
  dicta
  didact
  didactic
  diva
  ducat
  tacit
  tact
  tactic
  taut