Center letter: r
Outer letter: a c i n t u
Answers (55):
  curtain
  taciturn
  antarctic
  arancini
  arcana
  arctic
  aria
  arnica
  arrant
  atria
  attar
  attract
  attractant
  aura
  cairn
  carat
  cart
  cataract
  circa
  circuit
  cirri
  citric
  crania
  critic
  currant
  curt
  incur
  inurn
  irritant
  narc
  nitric
  rain
  raita
  rani
  rant
  ratatat
  rattan
  ricin
  ruin
  runic
  runt
  tantara
  tantra
  tantric
  tart
  tartan
  tartar
  tiara
  tract
  train
  trait
  truant
  turn
  unitarian
  uric