Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
† 1. mētrŏpŏlis, is, f., = μητρόπολις, a city from which other cities have been colonized, a mother-city; also, the chief city, metropolis of a province (post-class.).
2. Mētrŏpŏlis, is, f., = Μητρόπολις, the proper name of several cities, e. g. in Thessaly, between Pharsalus and Gomphi, Caes. B. C. 3, 80; Liv. 32, 13, 11.
Mētrŏ-pŏlītae, ārum, m., the inhabitants of Metropolis, Caes. B. C. 3, 81; cf. of others, Plin. 5, 29, 29, § 106; 5, 29, 31, § 120.