1. In Greek mythology, Zeus was the "Father of God and Men," "Master of the Celestial Fire." His chief weapon and symbol was the thunderbolt.
He was the son of Chronos, one of the 12 Titans, and Rhea, who were both children of Uranos (Heaven) and Gaea (Earth). Chronos was deposed by his youngest son, Zeus. A long period of wars between the Gods started, till in the final battle, Zeus (together with his daughter Athena) defeated the serpent-god Typhon, and became the Leader, the Supreme deity.
Zeus shared control with other deities in the Olympian Circle. The twelve Members of the (first) Olympian circle were:

These were the original twelve. Soon they were to be joined by:

The name Zeus may come from the Indian Hindu God Dyaus.

2. Zeus also is the name of a covert programme to create weapons that could be used in case of an extra-terrestrial attack. See Zeus project.