Fat Man

American  

noun

1. the code name for the plutonium-core, implosion-type atom bomb the U.S. first tested and then dropped on Nagasaki in 1945.

---

Compare meaning

How does fat-man compare to similar and commonly confused words? Explore the most common comparisons:

• Fat Man vs. Little Boy

Example Sentences

Fat Man and Little Boy are holding steady. apnews.com/article/dei-...

From Salon • Mar. 10, 2025

Katie Hafner: So pretty much all of Los Alamos then retrenched around a different design, an implosion weapon that would become the Trinity device and then the Fat Man bomb that was dropped on Nagasaki.

From Scientific American • Aug. 3, 2023

It then made plutonium that fueled the Fat Man atomic bomb dropped on Nagasaki, Japan, in August 1945, that led to the end of Word War II.

From Seattle Times • May 23, 2022

Fat Man, a plutonium bomb of the kind tested at Trinity, was used on Nagasaki on Aug. 9, and the end of World War II soon followed.

From New York Times • Aug. 3, 2021

Fat Man exploded over the city of Nagasaki with the force of 22,000 tons of TNT.

From "Bomb" by Steve Sheinkin