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 Department of Defense, now called the War Department, is investing directly in companies, demanding greater production and new technology.

From Barron's • Jan. 14, 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

An officer left the War Department and delivered death warrants to the defendants Mary Surratt, David Herold, George Atzerodt, and Lewis Powell.

From "Chasing Lincoln's Killer" by James L. Swanson