Where does the term "scapegoat" come from and what is its biblical role?
The word scapegoat was coined by William Tyndale in his 1530 translation of the Bible. It is a compound word from the roots escape and goat. The word was used to translate the name of one of the two goats mentioned in Leviticus 16 -- literally, the one who escaped death.
The two goats in Leviticus are integral components of the Yom Kippur festival of ancient Israel. Yom Kippur is better known as the Day of Atonement and Leviticus 16 describes its first observance. In its description it outlines the statutes to be followed in all future Yom Kippur observances. One of the key features of this holiday is the sacrifice of these two goats.
Two male goats were selected and brought to the sanctuary. The high priest then drew lots between the two. The first goat was sacrificed as a sin offering to purify the Holy of Holies -- the innermost room of the sanctuary -- from the sins of the people. Later, the second goat was brought before the High Priest. This animal Tyndale called the scapegoat. The high priest would lay his hands on the goat's head and confess all the sins, iniquities, and transgressions of the Israelites so that "he shall put them upon the head of the goat" (Lev. 16.21b). Then the goat was led out into the wilderness "for Azazel" (16.10) and released. And "the goat shall bear all their iniquities upon him to a solitary land" (16.22).
The question is, who/what is Azazel?
Tyndale interpreted the Hebrew word Azazel as "scapegoat." Thus the Leviticus passage above would read the "goat was led out into the wilderness as a scapegoat." The problem is, the literal meaning of the word Azazel doesn't have anything to do with goats. Further, in the apocryphal book of Enoch, Azazel is more than a just a goat who escaped -- Azazel is a fallen angel, a demon, who lives in the wilderness. The literal meaning of the word Azazel confirms this: Azazel means "strong" or "angry" god.
Everything done in a religion has some sort of meaning; so what does it mean that one of the goats was "blessed" with all the sins of the Israelites and then sent out into the wilderness for Azazel?
Traditionally it was understood that the sins of the Israelites were forgiven because the first goat was sacrificed to YHWH as a sin offering. Indeed, according to Hebrews 9.22 "without the shedding of blood there is no forgiveness of sins." Thus the sacrifice of the first goat brought about that forgiveness.
However, there seems to be more to forgiveness than just blood in this case. The first goat's blood was sprinkled on the Ark of the Covenant, on the floor of the Holy of Holies, and on the sanctuary itself so the whole structure was purified from sin. However, when the sin was removed from the sanctuary and its furnishings it seems that it became attached to the priest. In other words, we have a vicious circle. When a sacrifice is made, the sin goes from the people to the altar. When the alter is cleansed by another sacrifice, the sin leaves the altar and attaches itself to the priest. If the priest were to offer another sacrifice, he would be cleansed, but the altar would be polluted again. To break the cycle, something different had to happen. That's where the second goat comes in. The second goat was blessed by the priest and all the sins of the nation were transferred from the priest to the goat. Then the goat was sent out alive into the wilderness to Azazel -- thus the sins were carried away from the people and the sanctuary. But why was the goat sent specifically to Azazel?
Some have argued that this goat was a sacrifice to the demon of the wilderness. If this is the case, the theology would later be changed when the commandment was added that the Israelites "may no longer offer their sacrifices for goat-demons" (Leviticus 17.7). In any event, the notion that the High Priest of Israel would offer a sacrifice to anyone but God seems abhorrent, and yet the text stands as written.
On the other hand, some believe the scapegoat was sent to the wilderness and to Azazel to symbolically demonstrate that the sins had been dispatched to the place of the dead.
In either case, the scapegoat was the symbolic bearer of the sins of the Israelites and when it was driven out into the wilderness, with it went the guilt and shame of the nation.