Definitions of Jefferson:

• noun:   3rd President of the United States; chief drafter of the Declaration of Independence; made the Louisiana Purchase in 1803 and sent out the Lewis and Clark Expedition to explore it (1743-1826)
• name:  A surname (common: 1 in 4000 families; popularity rank in the U.S.: #460)
• name:  A male given name (rare: 1 in 10000 males; popularity rank in the U.S.: #662)