How broad is the definition of sodomy?
Solution 1:
You probably already know that sodomy is derived from "sin of Sodom" from the Bible story in which God rained fire and brimstone down on Sodom and Gomorrah for certain reasons.
My understanding is that some interpretations of these reasons are that God's angel messengers were (nearly) raped by the residents, so this meant that God objected to homosexuality. Therefore the "sin of Sodom" was homosexuality, which naturally was further interpreted as anal sex between two men. However, other interpretations might suggest any kind of "unnatural" sex act, including bestiality, oral sex, anal sex between any two people, and pretty much anything that's not missionary-style intravaginal intercourse.
Since what actually constitutes the "sin of Sodom" is open to debate, I imagine the definition of the word sodomy is also pretty fluid.
The dictionary definitions that I have found generally specify sodomy as anal sex, some include oral sex, and some include bestiality. This article has a quick reference as far as legal definitions of sodomy in the US.
I don't know a good history of sodomy, so I hope someone posts one, but I think that it is likely that oral sex and bestiality have been part of the definition since the beginning.
Solution 2:
Sodomy most definitely does mean "anal sex" and usually connotes the male-to-male variety.
Origin from Etymonline:
sodomy c.1300, from O.Fr. sodomie, from L.L. peccatum Sodomiticum "anal sex," lit. "sin of Sodom," from L. Sodoma (see Sodom).
NOAD gives a little more info:
ORIGIN Middle English : from medieval Latin sodomia, from late Latin peccatum Sodomiticum ‘sin of Sodom’ (after Gen. 19:5, which implies that the men of Sodom practiced homosexual rape) (see Sodom).
But NOAD also includes this extra tidbit about oral sex:
sodomy |ˈsädəmē| noun sexual intercourse involving anal or oral copulation.
Probably the distinction is blurred; people of a certain era weren't all that clear on what the "sin of Sodom" might mean, and preachers were no doubt loath to explain in detail. So the word probably acquired the extra meaning of "anything that good, church-going folk might construe to be an abomination of the sexual kind." Oral sex would have been included under that rubric.
Solution 3:
According to the Oxford English Dictionary, the original meaning of sodomy was:
Originally: any form of sexual intercourse considered to be unnatural. Now chiefly: anal intercourse
This word was first used in the 13th century:
1297 R. Gloucester's Chron. (Rolls) 9038 Mid þe vile sunne of sodomye yproued hii were echon.
Even in the early 1900s, it still seems to be used to mean sexual acts besides anal intercourse:
1905 H. B. Lazell Clark & Marshall's Treat. Law of Crimes (ed. 2) ix. v. §461. 706 Sodomy or buggery, which is sexual connection by a man or woman with a brute animal, or connection per anum by a man with any other man, or with a woman, is a felony at common law.
However, by the late 1900s it was used as we use it now--to primarily refer to the acts of anal intercourse:
1980 D. C. Knutsen Homosexality & Law 33 Missouri has reduced consensual sodomy by adults in private from a felony to misdeneanour status.
So the phrase sodomy started out with a very broad definition, which then became more specific as time went on. As Kith mentioned, the only "good" type of sexual intercourse would have been heterosexual inter-vaginal missionary intercourse.
Solution 4:
I think originally it might have been meant to describe any sexual act between two people or man and/or woman and animal that could not result in procreation of humans.