War Department

American  

noun

U.S. History.

1. the department of the federal government that, from 1789 until 1947, was responsible for defense and the military establishment: in 1947 it became the Department of the Army, which became part of the Department of Defense when it was established in 1949.

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Example Sentences

President Abraham Lincoln spent many evenings in the War Department telegraph office reading dispatches and issuing orders.

From The Wall Street Journal • Apr. 26, 2026

“The president has made it clear that you will not have a nuclear weapon. The War Department agrees,” Hegseth told reporters Tuesday in the Oval Office.

From Los Angeles Times • Mar. 25, 2026

“The first sinking of an enemy ship by a torpedo since World War II. Like in that war back when we were still the War Department, we are fighting to win.”

From Barron's • Mar. 6, 2026

He reverses a post-World War II decision that renamed the War Department the Department of Defense, returning its meaning to “war.”

From Salon • Nov. 8, 2025

In late 1791 the War Department put Major General “Mad” Anthony Wayne in charge of restructuring the army units under his command so they could function as irregular forces in Ohio.

From "An Indigenous People’s History of the United States" by Roxanne Dunbar-Ortiz