metros

noun
  1. 1

    An underground railway.

  2. 2

    A train that runs on such an underground railway.

  3. 3

    An urban rapid transit light railway

  4. 4

    A train that runs on such a railway.

noun
  1. 1

    A metropolitan area

Source: https://en.wiktionary.org/wiki/metro, https://en.wiktionary.org/wiki/metros