Quick definitions from WordNet (Lewis and clark expedition)
▸ noun: an expedition sent by Thomas Jefferson to explore the northwestern territories of the United States; led by Merriwether Lewis and William Clark; traveled from St. Louis to the mouth of the Columbia River from 1803 to 1806
▸ noun: an expedition sent by Thomas Jefferson to explore the northwestern territories of the United States; led by Merriwether Lewis and William Clark; traveled from St. Louis to the mouth of the Columbia River from 1803 to 1806