WordNet (r) 3.0 (2006):

Red Sea
    n 1: a long arm of the Indian Ocean between northeast Africa and
         Arabia; linked to the Mediterranean at the north end by the
         Suez Canal

Easton's 1897 Bible Dictionary:

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.).