a seaport of British India, in the district of South Arcot, presidency of Madras, at the mouth of the river Vellaur, 116 miles S. of Madras. It was at one time a place of much importance, but it suffered very severely in the wars of the British government against Mysore, and fell into a state of decay. It is now, however, in a more prosperous condition, chiefly on account of the extensive iron-works, which have been established here. The ore is obtained in abundance in the vicinity, and may be made into the finest steel. At Porto Novo, Hyder Ali, with an immensely superior army, was totally defeated by the British under Sir Eyre Coote in 1791.