This
jawbreaker is a
word that means "
the practice of using long words", and is therefore
self-referential. (grin)
Composed of 32 letters, it is far longer than its synonym sesquipedalium words,, from Horace's sesquipedalia verbs, words a foot and a half long. Greek, too, has a word for mile-long words: amaxiaia remata, "words large enough for a wagon."
See also: Bovine