Etymology

The origin of the name is not exactly known. There are various theories. One theory is that the region is named after a nickname of Amar bin Qahtan (عمرو بن قحطان), meaning "death has come", from /ḥaḍara/ (Arabic for "has come") and /maut/ ("death"), the reason being that whenever he entered a battle, there were always many people who died.^{[citation needed]}
Another theory is that it is related to Hazarmaveth in Genesis 10:26 and 1 Chronicles 1:20 in the Bible (meaning "court of death", according to various Bible dictionaries). There, Hazarmaveth is the name of a son of Joktan, one of the sons of Shem in the table of the Sons of Noah in Genesis 10—i.e., the founders of nearby nations including Sheba, also a son of Joktan. As Southern Arabia was and is one of the homelands of the South Semitic language subfamily, a Semitic origin for the name is highly likely. If the name did reflect a biblical- or pre-biblical-era naming convention in the Near East, this would make it ancient indeed, pre-dating both Islam and Greco-Roman civilization.
A third theory is that the name derives from the Greek υδρευματα (hydreumata), or enclosed (and often fortified) watering stations at wadis. A hydreuma (singular) is a manned and fortified watering hole or way station along a caravan route. Juris Zarins, rediscoverer of the city claimed to be the ancient Incense Road trade capital Ubar in Oman, described that site in a Nova interview:

The site that we uncovered at Shisur was a kind of fortress/administration center set up to protect the water supply from raiding Bedouin tribes. Surrounding the site, as far as six miles away, were smaller villages, which served as small-scale encampments for the caravans. An interesting parallel to this are the fortified water holes in the Eastern Desert of Egypt from Roman times. There, they were called hydreumata.