My kid asked me this one and as the family know-it-all (OK - The family smartass - Close enough!) I don’t want to disappoint him.
It gets its name from the fact that it sometimes has algae blooms, which turn the the water reddish when they die.
I once did a search on this, and the best explanation I found was it was translated through several languages, and the original Egyptian term was actually “Sea of Reeds.” By the time the Bible and other ancient writings got through being translated into various European languages, it somehow ended up being the Red Sea in English.
Now I’m curious, is it La Mere Rouge, in French?
Carina, the Sea of Reeds and the Red Sea are two different bodies of water. JeffB’s answer is the correct one.
Then why is the Hebrew name for the Red Sea Yam Soof, or “Reed Sea”? I can assure you, the Hebrew name is older than the English one.
Besides, the Red Sea is clear, warm, calm and the home of some kick-ass coral reefs - but it does not have any reddish algae.
Because Cecil said the Red Sea isn’t the Sea of Reeds, that’s why. I was always told because of the deaths in it… Oh yeah, and isn’t it the Nile that turns red like that?
“Reddish algae” would be a neat explanation, except that there isn’t any.
The name actually comes from the redddish color of the desert cliffs along its shores.
I had heard the red algae reason. I don’t think it means the water stays red. I thought the Red Sea was just prone to “red tide” algae blooms like you get along the Gulf of Mexico.
If you want to trust Captain Nemo, in 20,000 Leagues Under the Sea, he uses red algae as the reason for the Red Sea name.
Although he also has an underwater tunnel between the Red Sea and the Meriterainian Sea, so he may not always be right. 
Red Sea The sea so called extends along the west coast of Arabia for about 1,400 miles, and
separates Asia from Africa. It is connected with the Indian Ocean, of which it is an arm, by the
Strait of Bab-el-Mandeb. At a point (Ras Mohammed) about 200 miles from its nothern extremity
it is divided into two arms, that on the east called the AElanitic Gulf, now the Bahr el-'Akabah,
about 100 miles long by 15 broad, and that on the west the Gulf of Suez, about 150 miles long by
about 20 broad. This branch is now connected with the Mediterranean by the Suez Canal. Between
these two arms lies the Sinaitic Peninsula. The Hebrew name generally given to this sea is Yam
Suph. This word suph means a woolly kind of sea-weed, which the sea casts up in great
abundance on its shores. In these passages, Ex. 10:19; 13:18; 15:4, 22; 23:31; Num. 14:25, etc., the
Hebrew name is always translated “Red Sea,” which was the name given to it by the Greeks. The
origin of this name (Red Sea) is uncertain. Some think it is derived from the red colour of the
mountains on the western shore; others from the red coral found in the sea, or the red appearance
sometimes given to the water by certain zoophytes floating in it. In the New Testament (Acts
7:36; Heb. 11:29) this name is given to the Gulf of Suez. This sea was also called by the Hebrews
Yam-mitstraim, i.e., “the Egyptian sea” (Isa. 11:15), and simply Ha-yam, “the sea” (Ex. 14:2, 9, 16,
21, 28; Josh. 24:6, 7; Isa. 10:26, etc.). The great historical event connected with the Red Sea is
the passage of the children of Israel, and the overthrow of the Egyptians, to which there is
frequent reference in Scripture (Ex. 14, 15; Num. 33:8; Deut. 11:4; Josh. 2:10; Judg. 11:16; 2 Sam.
22:16; Neh. 9:9-11; Ps. 66:6; Isa. 10:26; Acts 7:36, etc.).
The mountains on the eastern shore are indeed reddish. They are in the land of Edom - which in Hebrew is “red”.
Hrm, well, I haven’t been to Saudi Arabia, but the mountains in Sinai and in the southern part of Israel are both reddish. Not that it matters, as the correct answer is the Yam Suf/Sea of Reeds one.
Curwin - isn’t Edom further north, across from the Dead Sea?
http://www.straightdope.com/classics/a1_035b.html
**
And there you have it, from the master, as Speaker for the Dead already said.
Quix
Here’s the quote from the Brittanica:
http://www.britannica.com/bcom/eb/article/6/0,5716,32566+1+32019,00.html?query=edom
I guess if I want the final answer on this I will just have to wait on Cecil. (Are you listening?)
Actually, there is still alot of dissent on the location of the “Sea of Reeds”. Some erudite sources claim it is indeed the Red Sea…I’m not sure there is a definitive answer. I did a quick search again, and got confused. There was even some arcane reference to the Red Sea actually being the blood flowing through our bodies, and the name being merely allegorical and not specifically referring to what we now call the Red Sea.
I have been there twice, most recently last June. As I recall, all the mountains & desert along that coast were a moonscapey-looking grey brown. So far the best snorkelling I’ve ever experienced.
I was just getting ready to post this same point. Some conjecture that the body of water called Yam Soof “Reed Sea” (thank, Alessan) in the book of Exodus is not the same body of water we call the Red Sea today. Here’s one site that talks about it.
I also saw this of an [url=“http://www.tourism.egnet.net/attraction/cities/red_sea/redsea.htm”]Egyptian tourism site[/ulr]:
I don’t know how far back the name “Red Sea” (in whatever language) goes back. I’d be curious to find out the name in Arabic. It’s possible that Yam Soof got applied to the Red Sea at a later point.
The Arabic name for the Red Sea is *Bahr al-Qulzum. * Unfortunately, I have no idea what qulzum means in Arabic, if it means anything at all other than being a proper name. (I’m writing from work and I would have to get home to look it up in my Arabic dictionary.)
Our use of the name “Red Sea” is a translation from the ancient Greek Pontos Erythraios.
Excuse me, Kyla, but how do you get from Hebrew suph (aquatic plant biomass) to Greek erythraios (red)?
The Greek name as a translation from Hebrew Edom makes the most sense of all. In Hebrew, the root aleph-daleth-mem means both ‘red’ and ‘earth’ – as such, it provided the name of Adam* as well as Edom. It makes sense as a name for a red earth land.
The brownish cliffs along the shore of the Red Sea sure look reddish in the sunset! Also (and there have been some threads here about color naming/color perception), in many ancient languages there is no word for “brown”, so the word for “red” is applied to brown things. For example, in Malay the words for “brown rice” and “brown sugar” are beras merah and gula merah. Merah means ‘red’.
*In Kabbalistic symbolism, the letter aleph represents the element Air. The Hebrew word dam means ‘blood’. The iron in blood’s hemoglobin turns red through oxidation, through breath of air, and Adam was formed of the earth plus the breath of God, the breath of life (neshamah) making his blood red, making him a living man of red earth. (Coincidentally, dam is Persian for ‘breath’).
I defintely agree. When I was there many years ago, the reflection of the surrounding desert through the water made the water reddish, regardless of the historical naming defivatives. The name RED is appropriate. You got to be there to see it yourself.
Qulzum is an old name for the city that is known today as Suez.
If you look at a map of the Read sea, you’ll notice that the Sinai peninsula divides it into two forks: the Gulf of Aqaba on the east, and the Gulf of Suez on the west. So, if you were intening to traverse the Suez canal, going into the Gulf of Aqaba would be most unforktunate. But anyway. . .
The word Qulzum may not be Arabic. It might be only an Arabic version of a previously named city (much the same as Memphis is a Greek corruption of the Egyptian name of the same city). So, “Bahr al-Qulzum” is really just another name for “Gulf of Suez,” just using an older name of the city.
So, if the previously mentioned information is correct, “Bahr al-Qulzum” includes both the Gulf of Suez and the Red Sea.