national academy of sciences
nongovernmental American organization of scientists and engineers, established March 3, 1863, by act of Congress to serve as an official adviser to the government in all matters of science and technology. It is a self-perpetuating body of limited membership; new members are co-opted on the basis of distinguished contributions to research.
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|an arrangement of five objects, as trees, in a square or rectangle, one at each corner and one in the middle.|
|a screen or mat covered with a dark material for shielding a camera lens from excess light or glare.|