Zain is the seventh letter of the Syriac abjad, with the numeral value seven. It writes z, a voiced alveolar sibilant, and unlike the six letters with hard and soft readings it has no second value. It joins only to the right, so the letter after it begins a new connected group.
In the Estrangela hand zain is a short stroke, and a beginner confuses it readily with dalath and with rish, which are also short strokes distinguished by a point. Learning which of the three a point belongs to, and which of them carries no point at all, is one of the first things a reader of manuscripts has to settle. In the later hands the three are drawn further apart, but the family resemblance survives.
Its name is the inherited Northwest Semitic word for a weapon, and zain stands at the same seventh place it holds in Hebrew, where the cognate letter is zayin. The place and the numeral value come from the same inheritance, the twenty-two letter Aramaic sequence that Syriac took over unchanged.
Because it joins only to the right, zain breaks a word into more than one connected run, and it is one of eight Syriac letters that do so. The others are alaph, dalath, he, waw, sadhe, rish and taw. Those breaks are part of what makes joined Syriac legible rather than one unbroken stroke.