Metro (noun)

A rapid transit system, typically underground, serving a city or urban area.

Origin:

From the latin metropolis, meaning mother city or capital. first used in the early 19th century to refer to an underground railway system.

Examples:

1. I always take the metro to work because it's faster than driving.
2. The metro system in Paris is one of the most extensive and well-used in the world.
3. The metro is a convenient and efficient way to get around the city.
4. The metro is a cost-effective mode of transportation for city-dwellers.
5. The metro had been shut down for maintenance, causing major delays for commuters.