|The Greater Tokyo Area is the largest metropolitan area in the world|
We start with urban meaning "characteristic of city life," which goes back to the 1600s but really came into usage in the early 1800s. It comes from the Latin urbanus "of or pertaining to a city or city life," and as a noun, "city dweller."
The word urbane came to be be associated with the manners of a person (especially a man) being suave, courteous, and refined in a way associated with city dwellers in contrast to those from rural areas.
A metropolis is a very large city or urban area which is a significant economic, political and cultural center for a country or region, and an important hub for regional or international connections and communications.
The word comes from Greek and means the "mother city" of a larger colony. In the ancient sense, it was a city which sent out settlers.
Later it came to mean more generally a city regarded as a center of a specified activity, or a large, important city in a nation.
Some of the ancient metropolises have survived until today and so are among the world's oldest continuously inhabited cities.
It combines the Greek word mḗtēr meaning "mother" and pólis meaning "city"/"town." Greek colonies of antiquity used the term to refer to their original cities with which they generally retained political-cultural connections.
The word was used in post-classical Latin for the chief city of a province, the seat of the government and, in particular, ecclesiastically for the seat of a metropolitan bishop.
Today the word has come to refer to a metropolitan area, a set of adjacent and interconnected cities clustered around a major urban center. In this sense metropolitan usually means "spanning the whole metropolis," as in "metropolitan administration" or "metropolitan life."
On a darker note, the word necropolis meant a large cemetery of an ancient or modern city from Late Latin, meaning literally "city of the dead" which goes back to the Greek necro (death) and polis again.
The word citadel goes back to the late 1500s and always meant a "fortress commanding a city." Its roots are in the French citadelle, Italian cittadella, which is a dimuative form of the older Italian cittade "city."
The word suburb probably seems like a modern term but it goes back to the mid-14th century and means a "residential area outside a town or city." The first recorded usage of the term in English, according to the Oxford English Dictionary, was made by John Wycliffe in 1380, where the form subarbis was used.
Its origin is from the Old French suburbe, from Latin suburbium ("an outlying part of a city") from sub "below, near" and urbs for "city." The Old English word was actually underburg.
It's interesting that in earlier usage, suburbs of places like 17th century London meant something negative and was associated with an inferior lifestyle. A "suburban sinner" was slang for a "loose woman" or prostitute."
Suburbs first emerged on a large scale in the 19th and 20th centuries as a result of improved rail and road transport, which led to an increase in commuting. They tended to grow around cities that had an abundance of adjacent flat land. Any suburban area is referred to as a suburb, while suburban areas on the whole are referred to as the suburbs or suburbia, with the demonym for a suburb-dweller being suburbanite. The even more modern colloquial shortening gives us burb and the burbs.
A more modern city-related word is barrio which appears around 1841 meaning a "ward of a Spanish or Spanish-speaking city." In that way, a barrio was a district, much like a suburb.
The word has earlier roots in the Arabic barriya meaning "open country" from barr meaning "outside" of the city. In modern American English usage, it generally means a "Spanish-speaking district in a city" with an early (1939) reference being to the Sanish Harlem area in New York City.