a town of Portugal, in the province of Estremadura, 25 miles N. by W. of Lisbon. It has old walls and a castle, several churches, hospitals, and schools, and some trade in wine. The name has been rendered famous in history, by the lines which Wellington erected here in 1810 for the defence of Lisbon, and which he held against the French till they were compelled to retreat. Pop. 3326.