subway

The subway is a city train system that often runs under the streets. It is also called the metro or the underground, and in London people often say "the Tube." It is a fast way to move around a busy city without getting slowed down by traffic above ground.

You might take it to work, to visit friends, or to explore different parts of town. In British English, however, a subway often means a passage for people walking under a road. In everyday use, the city train meaning is the one most people know, especially in North America.

The term "subway" most often refers to an underground railway system used for local travel within a city. In North American English, this is the usual meaning. Similar systems may be called the "metro," the "underground," or, in London, "the Tube." The main idea is simple: trains carry people quickly through crowded urban areas, often below street level.

The history of this kind of system goes back to the 19th century. London's Metropolitan Railway, opened in 1863, is widely recognized as the world's first underground passenger railway. Since then, these systems have become a basic part of life in many major cities, including New York, Paris, Tokyo, and Mexico City. They do more than move people from place to place; stations can become landmarks, meeting points, and lively public spaces.

Context matters, though. In British English, a "subway" usually means a pedestrian tunnel under a road rather than a train network. The word can also refer to a long sandwich, short for "submarine sandwich," especially in casual American English and brand names. Because of these different meanings, the surrounding words usually make it clear whether someone is talking about city transport, a walkway under a road, or food.