The Suburbs vs. the Urbs

Given that most of the common words in our language beginning sub- tend to have meanings concerned with “beneath” (as in subterranean and submarine) or “less than” (as with subpar), you would be forgiven for assuming that the suburbs were so named because of their location below, or their status as less than, their urban counterparts. Not so, however: sub- may have other meanings at the beginning of a word; in this case, it indicates not depth or inferiority, but proximity. In other words, the suburbs are a region close to the urbs.

Is urbs an English word? Yes; it is rarely used, but it refers typically to a city, particularly when distinguished from a suburb.