Saco (sôˈkō) [key], city (1990 pop. 15,181), York co., SW Maine, on the Saco River; settled 1631, inc. as Pepperellboro 1762; name changed to Saco 1805; inc. as a city 1867. Saco is named for the Sawatucke ethnic group and means "burnt pine." The city has an industrial park and makes diverse products, such as machinery, leather, and shoes. Thornton Academy is located there.