Amalthea, am-al-the a, in Greek mythology, the nurse of the infant Zeus, in Crete. According to one story Amalthea was a nymph and fed the child with goat's milk. Another legend gives the name of Amalthea to the goat itself, and says she suckled the infant. Zeus broke off one of the horns of this goat and endowed it with the power of being filled with whatever the possessor might wish. This horn was called the horn of plenty, or cornucopia, and it was used in later times as a symbol of plenty. There is another story which connects the origin of the cornucopia with Achelous. See ACHELOUS.