ARABIAN SEA, the name applied to the large sheet of water, really a portion of the Indian Ocean, bounded on the E. by Hindustan, on the N. by Beloochistan, on the W. by Arabia and the Gulf of Aden, and on the S. by an imaginary line stretching between Cape Guarclafiii, in the N.E. of Africa, and Cape Comoriu in Hindustan. This is the Arabian Sea proper, but under the name Gulf of Aden it penetrates between Africa and Arabia, connecting itself with the Red Sea through the Straits of Bab-el-Mandeb ; while on the N.W. the Gulf of Oman, with its continuation the Persian Gulf, separates Arabia from Beloochistan and Persia. Besides these larger ramifications, there are the Gulfs of Cambay and Cutch in the N.W. of India. An interest and importance belong to this sea as forming part of the chief highway between Britain and India. The islands it contains are few and insignificant, the chief being Socotra and the Laccadives. The Arabian Sea is more or less coextensive with the Mare Erythrceum or Rub rum of the ancients, although these terms seem to have been applied with considerable vagueness.