Also found in: Dictionary, Wikipedia.
a lake in South America; situated on the border between Chile and Argentina, on the eastern slope of the Patagonian Andes. Area, 1,010 sq km. Lake San Martin formed as terminal moraines dammed the flow of glacial meltwater from the South Patagonian Ice Field. In the southwest, O’Higgins Glacier descends directly to the lake. Lake San Martin drains through the Pascua River into Baker Channel of the Pacific Ocean. It was named for J. San Martin.