Digamma
Digamma , noun
[Greek {not transcribed}; {not transcribed} = {not transcribed} twice + ga`mma the letter G. So called because it resembled two gammas placed one above the other.]
(Greek Grammar) A letter ({not transcribed}, {not transcribed}) of the Greek alphabet, which early fell into disuse.
This form identifies it with the Latin F, though in sound it is said to have been nearer V. It was pronounced, probably, much like the English W.