Alpha, the beginning.
In Moralia, Ammonius asks Plutarch what he, being a Boetian, has to say for Cadmus, the Phoenician who reputedly settled in Thebes and introduced the alphabet to Greece, placing alpha first because it is the Phoenician name for ox..
"Nothing at all," Plutarch replied. He then added that he would rather be assisted by Lamprias, his own grandfather, than by Dionysus' grandfather, i.e. Cadmus. For Lamprias had said that the first articulate sound made is "alpha", because it is very plain and simple — the air coming off the mouth does not require any motion of the tongue — and therefore this is the first sound that children make.
According to Plutarch, alpha was connected with the Moon.