ZAYIN (Heb. ז; זַיִן), the seventh letter of the Hebrew alphabet: its numeral value is therefore 7. The earliest form of the zayin, in the c. 1500 b.c.e. Proto-Sinaitic inscriptions, consisted of two parallel strokes , which were later joined by a third stroke , . In the tenth century b.c.e. the letter was relatively high (thus also in the Archaic Greek script), but later became squat. In the Hebrew script it was written → , which developed into Samaritan , while in the Phoenician script it turned into (cf. Greek and Latin "Z") and . In the Aramaic script it was written as a wavy line which later dropped its extremities and then it turned into a vertical stroke . The vertical zayin was preserved in both the Nabatean and Jewish scripts. In Arabic – in order to distinguish it from the ra – a diacritic point was added to the za; in the Jewish script, as the vertical stroke was interchangeable with the waw, a rightward hook was added to the letter top. From this form the developed. See *Alphabet, Hebrew.
"Zayin." Encyclopaedia Judaica. . Encyclopedia.com. (January 21, 2019). https://www.encyclopedia.com/religion/encyclopedias-almanacs-transcripts-and-maps/zayin
"Zayin." Encyclopaedia Judaica. . Retrieved January 21, 2019 from Encyclopedia.com: https://www.encyclopedia.com/religion/encyclopedias-almanacs-transcripts-and-maps/zayin