canine letter

English

So called because it sometimes represents a sound like a dog's growl.

(archaic) The letter r.
- 1833, Thomas Keightley, Fairy Mythology, volume I, London: William Harrison Ainsworth, page 10:
  All the foregoing etymologies, be it observed, are the conjectures of English scholars; for the English is the only language in which the name of the individual, Fairy, has the canine letter to afford any foundation for them.