underground railroad

American  

noun

1. Also called underground railway.  a railroad running through a continuous tunnel, as under city streets; subway.

2. (often initial capital letters) (before the abolition of slavery) a system for helping African Americans fleeing slavery to escape into Canada or other places of safety.

---

underground railroad British  

noun

1. (often capitals) (in the pre-Civil War US) the system established by abolitionists to aid escaping slaves

---

Underground Railroad Cultural  

1. A network of houses and other places that abolitionists used to help slaves escape to freedom in the northern states or in Canada before the Civil War. The escaped slaves traveled from one “station” of the railroad to the next under cover of night. Harriet Tubman was the most prominent “conductor” on the Underground Railroad.

---

underground railroad Idioms  

1. A secret network for moving and housing fugitives, as in There's definitely an underground railroad helping women escape abusive husbands. This term, dating from the first half of the 1800s, alludes to the network that secretly transported runaway slaves through the northern states to Canada. It was revived more than a century later for similar escape routes.

---

Etymology

Origin of underground railroad

First recorded in 1825–35

Example Sentences

KCK also became a major stop on the underground railroad, escaped slaves gaining freedom the instant they crossed the river into Kansas, an abolitionist state.

From The Wall Street Journal • Dec. 28, 2025

The Seattle Men’s Chorus became an active stop on a modern underground railroad, an informal network of activists and nonprofits that helps LGBTQ+ people escape persecution and resettle in countries where they will be safe.

From Seattle Times • Feb. 14, 2024

A route from the North Korean border, running through China and into Southeast Asia, is marked out on it — the underground railroad to freedom for defectors.

From Washington Times • Nov. 22, 2023

April Mayes: She's the daughter of runaway slave Reverend Jermain Loguen, who was an abolitionist who operated a station of the underground railroad under his house in Syracuse, New York.

From Scientific American • Sep. 28, 2023

In any event, the music would soon cover their talk of the underground railroad.

From "The Underground Railroad: A Novel" by Colson Whitehead