[smith-soh-nee-uh
n] 
| an institution in Washington, D.C., founded 1846 with a grant left by James Smithson, for the increase and diffusion of knowledge: U.S. national museum and repository. |
A group of over a dozen museums and research and publication facilities, such as the National Air and Space Museum, the Museum of Natural History, the Museum of History and Technology, the National Zoo, and the National Gallery of Art. Many of the Smithsonian's buildings are on the Washington Mall. The institution is named after James Smithson, an Englishman whose bequest enabled its founding in the nineteenth century.