San (letter) San (letter) San (Ϻ) was an archaic letter of the Greek alphabet. Its shape was similar to modern M, or ϡ, or to a modern Greek Sigma (Σ) turned sideways, and it was used as an alternative to Sigma to denote the sound . Unlike Sigma, whose position in the alphabet is between Rho and Tau, San appeared between Pi and Qoppa in alphabetic order. In addition to denoting this separate archaic character, the name "San" was also used as an alternative name to denote the standard letter Sigma. The existence of the two competing letters Sigma and San is
Archaic Greek alphabets , and was probably an intermediate sound during the phonetic change from the earlier plosive clusters towards the later sound, possibly an affricate similar to . In one attested document, the Arcadocypriot Greek of Mantineia used an innovative letter similar to И (), probably derived from a variant of san, to denote what was probably a -like sound in environments reflecting etymological Proto-Greek . In the highly-divergent Pamphylian Greek, the letter digamma () existed side by side with another distinctive form . It has been surmised that in this dialect the sound may have changed to labiodental in some environments.