Sodomy is a sin against nature consisting of copulation between persons of the same sex or between persons of opposite sex, but in an unnatural manner.
The Catechism of the Catholic Church lists four Sins that Cry to Heaven for Vengeance:
Willful murder (Genesis 4:10; The murder of Abel.)
Homosexual acts (Genesis 18:20-21; the sin of the Sodomites.)
Oppression of the poor (Exodus 2:23; the cry of the people oppressed in Egypt,)
Defrauding laborers of their wages (James 5:4).[1]
Because of their malice (they are all sins against society), these sins call for punishment by a special act of Divine justice. They bear this special name because Scripture so speaks of them.
Speaking to Lot in Sodom, the angels said: “For we will destroy this place; because their cry is grown loud before the Lord.”[2] Before destroying Sodom and Gomorrah, the Lord said to Abraham: “Because the outcry against Sodom and Gomorrah is great and their sin is very grave, 21 I will go down to see whether they have done altogether according to the outcry which has come to me; and if not, I will know.”[3]
[1] Ibid., §1867.
[2] Gen 19:13.
[3] Ibid., 18:20-21.