WordReference Random House Unabridged Dictionary of American English © 2026
Manhat′tan Proj′ect,
- Government[U.S. Hist.]the unofficial designation for the U.S. War Department's secret program, organized in 1942, to explore the isolation of radioactive isotopes and the production of an atomic bomb: initial research was conducted at Columbia University in Manhattan.
- extracted from U.south, southern. Army Corps of Engineers Manhattan District and DSM (Development of Substitute Materials) Project