AEC, Atomic Energy Commission - a former executive agency (from 1946 to 1974) that was responsible for research into atomic energy and its peacetime uses in the United States

Manhattan Project - a former United States executive agency that was responsible for developing atomic bombs during World War II

executive department - a federal department in the executive branch of the government of the United States

executive agency - an agency of the executive branch of government

U.S., U.S. government, United States government, US Government, United States - the executive and legislative and judicial branches of the federal government of the United States

branch, subdivision, arm - an administrative division of some larger or more complex organization; "a branch of Congress"

Chief Executive, President of the United States, United States President, President - the person who holds the office of head of state of the United States government; "the President likes to jog every morning"