Etymology of the Greek word metropolis (μητρόπολις)
the Greek word metropolis, μητρόπολις (a mother city; 'metropolis')
derived from the Greek word polis, πόλις (a town (properly, with walls, of greater or less size))
derived from the Proto-Indo-European root *pelə-
derived from the Greek word meter, μήτηρ (a 'mother' (literally or figuratively, immediate or remote))