What city is the smithsonian institution located? The Smithsonian Institution was a collection of museums and research organizations, many of which were located in the city of Washington, DC on Earth. It was initially formed in 1846 in the United States of America, for the "diffusion of knowledge amongst men.".What does smithsonian institution mean? Freebase (0.00 / 0 votes)Rate this definition: The Smithsonian Institution, established in 1846 "for the increase and diffusion of knowledge", is a group of museums and research centers administered by the United States government. Termed "the nation's attic" for its eclectic holdings of 137 million items, the Institution's Washington, D.C.What is the abbreviation for smithsonian institution? SI stands for Smithsonian Institution. Suggest new definition. This definition appears very frequently and is found in the following Acronym Finder categories: Science, medicine, engineering, etc. Organizations, NGOs, schools, universities, etc. See other definitions of SI. Other Resources: We have 92 other meanings of SI in our Acronym Attic.Where is the smithsonian museum located? Location in Washington, D.C. The Smithsonian American Art Museum (commonly known as SAAM, and formerly the National Museum of American Art) is a museum in Washington, D.C., part of the Smithsonian Institution.