Breadcrumb Home > Thesaurus Cite Synonyms of subway system Find synonyms for: Noun1. metro, tube, underground, subway system, subway, railway, railroad, railroad line, railway line, railway systemusage: 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'"WordNet 3.0 Copyright © 2006 by Princeton University. All rights reserved. Related Content Daily Word Quiz: polemic Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language Synonyms Index