>Overheard in the office today:
(guy on the phone) Hey Jim, it’s me.. Could you please call the couple in stateroom 8084 and explain to them what makes the Red Sea red? I just don’t have the time or energy…
If they had looked outside, they would have seen that the Red Sea is not red.
This confused me as well, so I looked up this article in Wikipedia
Red Sea is a direct translation of the Greek Erythra Thalassa (Ερυθρά Θάλασσα), Latin Mare Rubrum, Arabic Al-Baḥr Al-Aḥmar (البحر الأحمر), and Tigrinya Qeyḥ bāḥrī (ቀይሕ ባሕሪ).
The name of the sea doesn’t indicate the color of the water since it is not red in color. It may signify the seasonal blooms of the red-colored cyanobacteria Trichodesmium erythraeum near the water surface. Some suggest that it refers to the mineral-rich red mountains nearby which are called Harei Edom (הרי אדום). Edom, meaning “ruddy complexion”, is also an alternative Hebrew name for the red-faced biblical character Esau (brother of Jacob), and the nation descended from him, the Edomites, which in turn provides yet another possible origin for Red Sea.
Another hypothesis is that the name comes from the Himyarite, a local group whose own name means red.
Yet another theory favored by some modern scholars is the name red is referring to the direction south, the same way the Black Sea’s name may refer to north. The basis of this theory is that some Asiatic languages used color words to refer to the cardinal directions. Herodotus on one occasion uses Red Sea and Southern Sea interchangeably.
A final theory suggests that it was named so because it borders the Egyptian Desert which the ancient Egyptians called the Dashret or “red land”; therefore it would have been the sea of the red land.