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
History of the Greek alphabet foreshadowed the development of vowel letters with a limited use of "matres lectionis", that is, consonants that pulled double duty as vowels, which for historical reasons occurred mostly at the ends of words. For example, the two letters "wāw" and "yōdh" stood for both the approximant consonants and , and the long vowels and in Phoenician. By this point in time, Greek had lost its sound, so Phoenician "yōdh" was used only for its vocalic value, becoming the Greek vowel letter iota . However, several Greek dialects still had a sound, and here "wāw" was used for both of its