The meaning of Capricornus in Latin is Horned Goat. It is one of the zodiac constellations and the area of the sky where it exists is known as the Sea. This is where the reference to Capricorn being a seagoat originates from. It is still one of 88 modern constellations and was also listed by Ptolemy as one of the 48 constellations he discovered. A diagram of the constellation is shown to the left.
In Greek mythology, Capricorn is known as Pan, the son of Hermes. In this though he is not a seagoat. Instead he had the upper half of a man and the legs of a goat. While Pan's mother was a nymph who shrieked and ran in fear when she saw her son, Hermes loved him. When Hermes took Pan to Olympus, the other gods and goddesses liked Pan as well. He then became the god of flockes and shepherds. Preferring the forests in the mountain over Olympus, Pan would play his reed-pipes and chase nymphs through the woods.