The letter M derives its shape from the Phoenician Mem, via the Greek letter Mu (µ), and from the Semitic letter Mem which originally pictured water. It is speculated that Semitic people working in Egypt c. 2000 BC borrowed a hieroglyph for water that was first used for an alveolar nasal "n" because of the Egyptian word for Water "n-t". This same symbol became used for M in Semitic because their word for water began with that sound. Water, being one of the basic elements for life, was chosen as the basis for our name.

Egyptian Hieroglyph "N"	Proto-Semitic M	Phoenician M	Etruscan M	Greek Mu