Titan

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun Greek Mythology One of a family of giants, the children of Uranus and Gaea, who sought to rule heaven and were overthrown and supplanted by the family of Zeus.
• noun One of prodigious size, strength, or achievement.
• noun The largest satellite of Saturn and the second largest satellite in the solar system.

from The Century Dictionary.

• noun In mythol., one of a race of primordial deities, children of Uranus and Ge (Heaven and Earth), or their son Titan, supposed to represent the various forces of nature.
• noun Any one of the immediate descendants of the Titans, as Prometheus and Epimetheus.
• noun The sun personified. Titan being at times substituted by the Latin poets for Helios as god of the sun.
• noun The sixth in order of the eight satellites of the planet Saturn, and the largest, appearing as a star of the ninth magnitude. See Saturn.
• noun A genus of beetles.
• noun A calcareous earth; titanite.
• noun Titanium.

from the GNU version of the Collaborative International Dictionary of English.

• adjective Titanic.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun Any of the giant gods in Greek mythology who preceded the Olympian gods.
• proper noun The largest moon of the planet Saturn.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun a person of exceptional importance and reputation
• noun (Greek mythology) any of the primordial giant gods who ruled the Earth until overthrown by Zeus; the Titans were offspring of Uranus (Heaven) and Gaea (Earth)
• noun the largest of the satellites of Saturn; has a hazy nitrogen atmosphere