Wordnet 3.0
NOUN (1)
1. 
 a seaway involving the Saint Lawrence River and the Great Lakes that was developed jointly by Canada and the United States; 
 oceangoing ships can travel as far west as Lake Superior; 
[syn: Saint Lawrence Seaway, St. Lawrence Seaway]
WordNet (r) 3.0 (2006):
Saint Lawrence Seaway
    n 1: a seaway involving the Saint Lawrence River and the Great
         Lakes that was developed jointly by Canada and the United
         States; oceangoing ships can travel as far west as Lake
         Superior [syn: Saint Lawrence Seaway, St. Lawrence
         Seaway]