Mah is an ancient Persian god of the moon, one of the Yazatas. He is associated with the cow, which plays an important part in old-Iranian mythology, and presides over time and tide. He is mentioned as an assistant of Vohu Manah. The seventh day of the month is dedicated to Mah.

Mah is also the Persian name of a fish on the back of which the Earth is believed to rest. In popular Islamic mythology, the world sits on a rock, on the back of a bull, on a kamkam (meaning unknown), on the back of a fish, on water, on wind, and on the veil of darkness -- hence the Persian expression az mah ta mahi, 'from the moon to the fish'; i.e., throughout the whole universe.