Ath is a Prime Letter in the Miriadic language. It represents the primal, central Spirit from which all things flow. It is symbolized by what looks like a Tau cross. It is pronounced like the word 'bath' without the 'b' sound.
The letter ath is derived from the word 'Aether' or 'Ether', which is one way of describing the vast hidden energy in the World.
It is also described by Aleister Crowley, as a combination of the first letter of the Hebrew alphabet Aleph (א) and the last letter of the Hebrew Alphabet, Tau (ת), thus creating the word "ATh" (את). Crowley described this word as "essence" (since it is the root word of Aether)