suph

This is a borrowed Egyptian word for the reeds, rushes, and papyrus that crowd the edges of the Nile and its marshes. As a plain noun it appears only a handful of times, and almost every one is unmistakably a freshwater setting. When Moses' mother hides her baby by the river, she tucks the basket (itself woven from papyrus, גֹּמֶא) into the reeds along the bank, and Pharaoh's daughter later spots it there. In Isaiah's oracle against Egypt, the word stands beside another word for reed (קָנֶה) as the two together wither when the Nile dries up: a picture of the whole marsh dying.

The one odd occurrence is in Jonah's prayer from inside the fish, where the same word is wrapped about the drowning prophet's head in the open sea. Since papyrus does not grow in salt water, most take it there as a stretched, poetic use meaning tangled weeds or seaweed, though the reading is debated (see that verse).

The plant sense matters far beyond these few verses, because this is the same word that forms the second half of the famous name of the sea Israel crossed in the exodus.

In the great majority of its appearances the word is locked into the phrase yam suph, literally "sea of reeds," the body of water tied to the exodus and to the northern arms of what maps call the Red Sea. English Bibles almost always print "Red Sea" here, a rendering that came down through the ancient Greek and Latin translations rather than from the Hebrew itself, which speaks of reeds.

Two things make this phrase famously slippery. First, it does not point to one fixed body of water. Some verses clearly mean a saltwater gulf far from any reeds: Solomon's ships are launched at Ezion-geber "on the shore of the Sea of Reeds in the land of Edom," which can only be the Gulf of Aqaba. Yet the exodus verses read most naturally as a marshy lake near the eastern edge of Egypt. So the same name seems to cover more than one place.

Second, scholars disagree about what the word even means inside the phrase. Most read it as "reeds," pointing to a reedy lake near Egypt. A vocal minority argue the second word is instead a look-alike Hebrew word for "end" or "edge" (סוֹף), which would make it something like "sea at the end of the world," a sea of Israel's imagination as much as its geography. This is a genuine, unsettled debate rather than a settled fact.