Shin (letter) languages, as follows: In the Arabic alphabet, ' is at the original (21st) position in Abjadi order. A letter variant ' takes the place of Samekh at 15th position. "" represents , and is the 13th letter of the modern alphabet order and is written thus: The Arabic letter "šīn" was an acronym for "something" ( "šayʾ(un)" ) meaning the unknown in algebraic equations. In the transcription into Spanish, the Greek letter "chi" (χ) was used which was later transcribed into Latin "x". According to some sources, this is the origin of "x" used for the unknown in the equations.
Archaic Greek alphabets written like a (, ). The following summary of the principal characteristic forms of representative local Greek scripts is based on the chapters on each dialect in Jeffery (1961). Archaic Greek alphabets Many local variants of the Greek alphabet were employed in ancient Greece during the archaic and early classical periods, until they were replaced by the classical 24-letter alphabet that is the standard today, around 400 BC. All forms of the Greek alphabet were originally based on the shared inventory of the 22 symbols of the Phoenician alphabet, with the exception of the letter Samekh, whose Greek counterpart Xi