an electric railway operating below the surface of the ground (usually in a city)
"in Paris the subway system is called the `metro' and in London it is called the `tube' or the `underground'"
An underground railway, especially for mass transit of people in urban areas.
"The commuters rushed onto the subway to avoid traffic on the busy city streets."
In plain English: A subway is an underground train system that moves people quickly through cities by traveling beneath streets and buildings.
"We took the subway to get downtown because traffic was bad."
Usage: In American English, use subway to refer specifically to an underground train system or the act of riding it, whereas British speakers typically prefer the term tube or undergound. Avoid using this word for above-ground commuter trains unless they are part of a specific metro network that includes tunnels.
To travel by underground railway.
"We took the subway to avoid the heavy traffic on the surface streets."
In plain English: To subway means to move something quickly and secretly, usually by hiding it under your clothes or inside another object while walking through an area where you are not supposed to be seen carrying it.
"The train began to subway along the tracks at high speed during rush hour."
The word subway comes from combining the prefix sub- with way. It originally meant an underground path or passage.