The letter ‘M’ is the thirteenth in the alphabet. It is equivalent to the Semitic mem and the Greek mu (M). It's possible that the Semitic form is derived from an earlier symbol that represented ocean waves. Thera, Attica, and Corinth's early Greek forms are very similar to the early North Semitic rendering. A Lydian alphabet has a similar structure.The sole difference between these forms is the writing direction. The Etruscan form is similar but has a stroke added to it. Due to the rarity of this form in Etruscan, the Latin form may have been directly copied from the Chalcidian.