the GNU version of the Collaborative International Dictionary of English
n. A letter (�, �) of the Greek alphabet, which early fell into disuse.
The Century Dictionary and Cyclopedia
n. A letter corresponding in derivation and alphabetic place to the Latin and modern European F, once belonging to the Greek alphabet, and retained longest among the Æolians.
Word Usage
"As an element of deterrence, on the other hand, the threat to kill ten of theirs for every minor inconvenience to one of ours seems useful and proper, since deterrence is supposed to be a little daft. digamma"