Center letter: r
Outer letter: a c d k p t
Answers (34):
  trackpad
  apart
  apparat
  attar
  attract
  carat
  card
  carp
  carpark
  cart
  cataract
  crack
  crap
  dark
  dart
  drat
  karat
  kart
  packrat
  park
  parka
  part
  prat
  rack
  radar
  rapt
  ratatat
  rattrap
  tarp
  tart
  tartar
  track
  tract
  trap