Wiktionary
episemon
n. 1 An insignia or some other distinguishing symbol 2 The Greek letter digamma 3 A term for the digamma, koppa, or sampi as a Greek numeral sign.
Wikipedia
Episemon
Episēmon (Greek , from epi- "on" plus sēma "sign"; plural: episēma) is a Greek word that can mean:
- a distinguishing mark or symbol, also called parasēmon, especially in the following contexts:
- another name for the Greek letter Digamma, the numeral sign for "6"
- a generic term for all three Greek numeral signs (Digamma 6, Koppa 90, and Sampi 900) in the system of Greek numerals, or similar symbols in other scripts