Azazel

The name Azazel has its beginning in what Jewish historians and the Bible call the Day of Atonement. On this day two goats were chosen. One was named the Lord's Goat and the other Azazel (Leviticus 16). The Lord's Goat was slain and applied to the furniture of the tabernacles symbolically transferring the sins of Israel to the Sin bearer that atones for their sins. The sins was the transfer to Azazel and brought in the Wilderness, never again to contaminate Israel. The antitypical service is believed by some Christians to mean that divine justice demands that the instigator of sin (Satan) will ultimately bear the consequences of the sins of the world.

Actually, Azazel was the scapegoat. Once a year the priests would offer one goat for individual sin that would be killed. A second goat would be the scapegoat. They would confess all the sins of Israel, and heap them on the head of this goat. Then they would send the goat outside of the city walls, effectively removing the sins of the nation.
This can be found in the Old Testament of the Bible in Leviticus 16.
All the other uses of the name as super heroes or what have you, came after this one. This is the original meaning.
For more information about Azazel, please reference this site. http://www.gotquestions.org/Azazel-scapegoat.html.

The word "azaz" means rebellion or arrogance, and "el" means God, so this likely means "rebellion against God".

I heard a theory that this means "strength of God", but I'm not sure. "El" means God and Azaziah translates the "strength" in Hebrew, so maybe.
Azazel and Semyazza were the two angels that led the angelic group the Grigori, or Watchers, to mate with mortal women, creating the Nephilim. According to the apocryphal Book of Enoch and parts of the Old Testament, this is why God sent the Great Flood.

In the apocryphal Book of Enoch, Azazel is one of the chiefs of the fallen angels, who "taught men to make swords, and knives, and shields, and breastplates, and made known to them the metals of the earth and the art of working them, and bracelets, ornaments, and the use of antimony, and the beautifying of the eyelids, and all kinds of costly stones, and all colouring tinctures." (chapter 8, verse 1, translated by R. H. Charles).

It is also said that Azazel was the name of an Angel cast down from heaven much like Lucifer. In order to gain God's forgiveness Azazel was given the burden of bearing the Sins of man/others.