From Tar Valon Library
A similar entry appears in the Wheel of Time Companion confirming the information available in the main story arc.
Aldieb, "Westwind", the wind that brings the spring rains, in the Old Tongue was Moiraine's horse at the time of her arrival in the Two Rivers until her disappearance into the lands of the Eelfinn fighting Lanfear (TFoH, Ch. 51). She was a sleek white mare with an arched neck and quick steps as graceful as a girl dancing (TEotW, Ch. 4). Aldieb was well trained, but nervous in Shadar Logoth