Manhattan Project

American  

noun

1. U.S. History. 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.

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Manhattan Project British  

noun

1. (during World War II) the code name for the secret US project set up in 1942 to develop an atomic bomb

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Manhattan Project Cultural  

1. The code name for the effort to develop atomic bombs (see also atomic bomb) for the United States during World War II. The first controlled nuclear reaction took place in Chicago in 1942, and by 1945, bombs had been manufactured that used this chain reaction to produce great explosive force. The project was carried out in enormous secrecy. After a test explosion in July 1945, the United States dropped atomic bombs on the Japanese cities of Hiroshima (see also Hiroshima) and Nagasaki.

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Etymology

Origin of Manhattan Project

Extracted from U.S. Army Corps of Engineers Manhattan District and DSM (Development of Substitute Materials) Project

Example Sentences

See Examples For:

Manhattan Project

Speaking to the Wall Street Journal, Coxon likened A.I. development to the Manhattan Project, the U.S. effort that built the first atomic bombs.

From Slate ● Sep. 9, 2026

We’ve had plagues and climate change before, to some degree, but until the Manhattan Project, humans weren’t really in control of that kind of existential, destructive power.

From Salon ● Jun. 15, 2026

The pages capture the inner thoughts of someone who found himself at the center of history, as if Oppenheimer grabbed a pen and bared his soul during the Manhattan Project.

From The Wall Street Journal ● May 9, 2026

"It's like if the Manhattan Project announced the nuclear bomb within a cute little Calvin and Hobbes cartoon."

From Barron's ● Apr. 10, 2026

“Robert Oppenheimer was a brilliant physicist. He ran the Manhattan Project, which developed the atomic bomb. Oppenheimer tested the atomic bomb in the middle of a desert in New Mexico.”

From "The Fourteenth Goldfish" by Jennifer L. Holm