polis n.

"elevated part of a Greek city," often the site of original settlement and usually a citadel, 1660s, from Latinized form of Greek akropolis "citadel" (especially, with capital A-, that of Athens), from akros "highest, upper" (from PIE root *ak- "be sharp, rise (out) to a point, pierce") + polis "city" (see polis). The plural would be acropoles.

"man of the world; citizen of the world, one who is cosmopolitan in ideas or life," 1610s, from Latinized form of Greek kosmopolites "citizen of the world," from kosmos "world" (see cosmos) + polites "citizen," from polis "city" (see polis). In common use 17c. in a neutral sense; it faded in 18c. but was revived from c. 1800 with a tinge of reproachfulness (opposed to patriot).