From Hebrew zayin, the name of a Hebrew letter and a word historically meaning weapon or sword.
Zayin (also spelled Zayn or Zain in related traditions) is the seventh letter of the Hebrew alphabet, written as ז and corresponding phonetically to the sound *z*. In Hebrew, the letter's name derives from *zayin*, meaning "weapon" or "sword," a meaning reflected in its angular, blade-like written form. Each letter of the Hebrew alphabet carries layered significance in Kabbalistic and mystical tradition: Zayin represents the number seven, associated with the Sabbath, completion, and the divine rest following creation.
In Kabbalistic interpretation, Zayin embodies the power of speech to cut through illusion. As a given name, Zayin is rare but not without precedent. It belongs to a tradition — found in Jewish, and to some extent broader Semitic naming practice — of using individual letters or their associated meanings as names, a practice that treats the alphabet itself as sacred.
The related name Zayn (meaning "beauty" or "grace" in Arabic) is far more common and famous, particularly since its adoption by the British-Pakistani singer Zayn Malik. Zayin distinguishes itself by staying closer to the original Hebrew-letter form, appealing to parents interested in Kabbalistic, mystical, or Hebrew-rooted naming. There is something quietly powerful about naming a child for a letter — it suggests that the child's life will be a kind of language, a character in an ongoing script. Zayin, the sword-letter, the seventh, the completion-marker, carries that weight with a particular intensity.