Center letter: a
Outer letter: b c f i k l
Answers (49):
  backfill
  abaci
  aback
  acacia
  acai
  alack
  alfalfa
  alibi
  alkali
  baba
  babka
  bacilli
  back
  bail
  bailiff
  balalaika
  balk
  ball
  biblical
  bilabial
  blab
  black
  blackball
  cabal
  cabala
  calf
  call
  calla
  callback
  cilia
  clack
  facial
  fail
  fall
  fallback
  filial
  flab
  flack
  flail
  flak
  iliac
  kickback
  kickball
  labia
  labial
  lack
  laic
  laical
  lilac