* "I take the subway to work every day." (This is a common way to use the word, referring to an underground train system.)
* "The subway station was bustling with people during rush hour." (This sentence describes the activity at a subway station.)
* "We ordered a foot-long subway sandwich for lunch." (This sentence refers to the popular fast-food chain Subway.)
* "The tunnel was so narrow it felt like a subway." (This sentence uses "subway" metaphorically to describe a confined space.)
The specific meaning of "subway" depends on the context.