Princeton's WordNet(0.00 / 0 votes)Rate this definition: 1  deltoid, deltoid muscle, musculus deltoideus(adj) a large triangular muscle covering the shoulder joint and serving to abduct and flex and extend and rotate the arm. 2  deltoid(adj) triangular or suggesting a capital delta, with a point at the apex.
Founded in 1846, Washington, D.C.'s Smithsonian Institution is the world's largest museum and research center, with 19 museums and galleries, nine research facilities, and the National Zoological Park. Most of these attractions are located in and around the National Mall, between the Lincoln Memorial and the U.S. Capitol.
Washington, D.C., is located in the mid-Atlantic region of the U.S. East Coast. Due to the District of Columbia retrocession, the city has a total area of 68.3 square miles (177 km 2), of which 61.4 square miles (159 km 2) is land and 6.9 square miles (18 km 2) (10.16%) is water.he centers of all three branches of the federal government of the United States are in the District, including the Congress, President, and Supreme Court. Washington is home to many national monuments and museums, which are primarily situated on or around the National Mall.