AIX (or Aex) was the nymph or possibly goat wife of the god Pan. She was seduced by Zeus and bore him son named Aigipan.

Aix may be the same as Aix Amaltheia, the goatish nurse of Zeus in the Diktaion cave. She was also probably also identified with the primordial Gorgon Aix, whose skin was crafted into the aigis shield.

Pseudo-Hyginus, Astronomica 2. 13 (trans. Grant) (Roman mythographer C2nd A.D.) :
"[The constellation Capra.] Euhemerus [Greek writer C4th-3rd B.C.] says that a certain Aex was the wife of Pan. When she was embraced by Jove [Zeus] she bore a son whom she called son of Pan. So the child was called Aegipan, and Jove, Aegiochus. Since he was very fond of him, he placed in memory the form of a goat among the stars."

S22.3 AIX (LITERAL GOAT), PAN

Sources:

• Hyginus, Astronomica - Latin Mythography C2nd A.D.