Thayer's Greek Lexicon

 1. the Red Sea
  1) the Indian Ocean washing the shores of Arabia and Persia, with
its two gulfs, of which the one on the east is called the
Persian Gulf, the other on the opposite side the Arabian. In
the NT the phrase denotes the upper part of the Arabian Gulf
(the Heropolitie Gulf, so called [i.e. the Gulf of Suez]),
through which the Israelites made their passage out of Egypt
to the shore of Arabia.