Zayin = 7, ordinal 7, reduced 7, no final form. Spelled in full, זין = 7+10+50 = 67.
Meaning
Zayin is 'sword' or 'weapon', one of the twelve simples, and the seventh letter, which puts it at the Sabbath and at the seven days. Its 7 is the tradition's number of completion in time, and the letter's name carries the same ambivalence the tradition gives the sword: the weapon that cuts and the weapon that defends.