İstanbul

The gem is named for the country it was traded through, not where it formed.

French pierre turquoise means “Turkish stone.” The mineral reached Europe through Ottoman trade, so English named it for Turkey rather than for the Persian and Sinai mines that produced it.

The coin carries the same old name as the adjective.

Bezant comes through Old French from Byzantium. The coin and the word for convolution share a city three names ago.

The word for bureaucratic tangle is an old name for Istanbul.

Byzantium was the Greek city that became Constantinople and then Istanbul. Its later empire's reputation for intricate administration gave English the adjective.

The demonym is younger than the city by roughly sixteen centuries, because the official name only changed in 1930.

Istanbul became the sole official name of the city in 1930, when the Turkish postal service stopped delivering mail addressed to Constantinople. English formed Istanbulite with the same -ite suffix it uses in Muscovite and Israelite. Turkish itself uses a different pattern, Istanbullu, built with the suffix -lu rather than a borrowed Greek ending.