1. In Greek (and Roman) mythology, Apollo is the God of religious law and temple worship. He represented moral and divine laws, and stood for spiritual and physical purification and perfection. He was the first son of Zeus (Jupiter in Roman mythology), and Leto. He was feared by both Gods and men. He was the (twin) brother of Artemis. He was one of the Twelve Olympian Gods.
2. In the 60's, Apollo was the name of the American (NASA) space project to put man on the moon. All rockets that were part of this program also carried the name Apollo.