Center letter: i
Outer letter: a c n r t u
Answers (56):
  curtain
  taciturn
  acacia
  acai
  antarctic
  anti
  antic
  arancini
  arctic
  aria
  arnica
  atria
  attain
  attic
  cacti
  cairn
  cantina
  circa
  circuit
  cirri
  citric
  crania
  critic
  incant
  incur
  intact
  intuit
  inurn
  irritant
  niacin
  nitric
  rain
  raita
  rani
  ricin
  ruin
  runic
  tacit
  tactic
  tactician
  taint
  tannic
  tannin
  tantric
  tiara
  tinct
  tint
  titan
  titanic
  train
  trait
  tunic
  tutti
  unit
  unitarian
  uric