(St.), a sea-port town of Portugal, in the province of Estremadura, seated on a bay of the Atlantic Ocean, 21 miles south of Lisbon. It stands on an eminence, with a very strong castle built on a rock. The soil about it is fertile in corn, wine, and fruits; and it is furnished with good fish from the sea, and a small lake in the neighbourhood. Here they make great quantities of fine salt, which is carried to the American plantations. E. Long. 8° 54' N. Lat. 38° 22'.