pilcomayo

noun

1. a river in S central South America, flowing SE from S Bolivia along the boundary between Paraguay and Argentina to the Paraguay River at Asunción. 1000 miles (1610 km) long.

noun

1. a river in S central South America, rising in W central Bolivia and flowing southeast, forming the border between Argentina and Paraguay, to the Paraguay River at Asunción. Length: about 1600 km (1000 miles)