Definition of St. Lawrence Seaway in US English:

St. Lawrence Seaway

proper noun

  • A waterway in North America that flows for 2,342 miles (3,768 km) through the Great Lakes and along the course of the St. Lawrence River to the Atlantic Ocean. Consisting of channels connecting the lakes and a number of artificial sections that bypass the rapids in the river, it is open along its entire length to oceangoing vessels. It was inaugurated in 1959.