Lewis & Short

1. mētrŏpŏlītānus, a, um, adj. [1. metropolis], of or belonging to a metropolis, metropolitan (post-class.): nomen, Cod. Just. 11, 21, 1.
Esp. subst.: Mētrŏ-pŏlītānus, i, m., a metropolitan, the bishop of a metropolitan church, Sid. Ep. 7, 9.