Princeton's WordNet

1. Louis IX, Saint Louis, St. Louis(noun)

   king of France and son of Louis VIII; he led two unsuccessful Crusades; considered an ideal medieval king (1214-1270)

2. Saint Louis, St. Louis, Gateway to the West(noun)

   the largest city in Missouri; a busy river port on the Mississippi River near its confluence with the Missouri River; was an important staging area for wagon trains westward in the 19th century