Digamma,
waw, or
wau (uppercase: , lowercase: , numeral: ) is an
archaic letter of the
Greek alphabet. It originally stood for the sound but it has principally remained in use as a
Greek numeral for
6. Whereas it was originally called
waw or
wau, its most common appellation in classical Greek is
digamma; as a numeral, it was called
episēmon during the Byzantine era and is now known as
stigma after the value of the
Byzantine ligature combining σ-τ as ϛ.