Following is term definitions for these and others.
Census-designated places are geographical areas designated by the U.S. Census Bureau for the purposes of compiling demographic data. They are not actual jurisdictions under Pennsylvania law. Other unincorporated communities, such as villages, may be listed as well.
In law, an unincorporated area is a region of land that is not a part of any municipality. To "incorporate" in this context means to form a municipal corporation, a city or town with its own government. Thus, an unincorporated community is usually not subject to or taxed by a city government. Such regions are generally administered by default as a part of larger territorial divisions, such as a township, borough, county, state, province, canton, parish, or country. It is not unknown, but uncommon, for small towns in fiscal crisis to disincorporate in order to have services provided by a higher administration; an example is Cabazon, California, which disincorporated in 1972.
A borough is an administrative division of various countries. In principle, the term borough designates a self-governing township although, in practice, official use of the term varies widely.
The word 'borough' derives from a common Indo-European language cognate, meaning fort: compare borough, bury (England), burgh (Scotland), burg (Germany), bourg (France), burgo (Spain), borg (Scandinavia), borgo (Italy), burcht (Dutch). The incidence of these words as suffixes to place names (e.g. Canterbury, Strasbourg, Luxembourg, Edinburgh, Hamburg, Gothenburg), usually indicates that they were once fortified settlements.
In the Middle Ages, boroughs were settlements in England that were granted some self-government; burghs were the Scottish equivalent. In medieval England, boroughs were also entitled to elect members of parliament. The use of the word borough probably derives from the burghal system of Alfred the Great. Alfred set up a system of defensive strong points (Burhs); in order to maintain these settlements, he granted them a degree of autonomy. After the Norman Conquest, when certain towns were granted self-governance, the concept of the burh/borough seems to have been reused to mean a self-governing settlement.
The concept of the borough has been used repeatedly (and often differently) throughout the English-speaking world. Often, a borough is a single town with its own local government. However, in some cities it is a subdivision of the city (e.g. London, New York City, and Montreal). In such cases, the borough will normally have either limited powers delegated to it by the city's local government, or no powers at all. At certain times, London has had no overall city government and London boroughs were the main unit of local government for Londoners. In other places, such as Alaska, a borough does not designate a single township, but a whole region; Alaska's largest borough, the North Slope Borough, is comparable in area to the entire United Kingdom. In Australia, 'borough' can designate a town and its surrounding area, e.g. Borough of Queenscliffe.
Boroughs as administrative units are to be found in Ireland and the United Kingdom, more specifically in England and Northern Ireland. Boroughs also exist in the Canadian provinces of Quebec and Ontario, in some states of the United States, in Israel, and formerly in New Zealand.
A township (or municipality) is a settlement which has the status and powers of a unit of local government. Specific use of the term to describe political subdivisions has varied by country. Township (or municipality) is generally associated with an urban area. However there are many exceptions to this rule, especially in the U.S. In the Scottish Highlands the term describes a very small agrarian community, usually describing a local rural or semi-rural government within a county. "Municipality" refers to a town or "an area governed like a town". Small (in terms of population) rural subdivisions with limited administrative responsibilities are better referred to as "parishes" or "communities", and this (rather than "municipality") is the preferred translation of the expressions commune, gemeende, Gemeinte, comuna, obec, etc referred to below. In most countries, a municipality is the smallest administrative subdivision to have its own democratically elected representative leadership.
A town is a type of settlement ranging from a few to several thousand (occasionally hundreds of thousands) inhabitants, although it may be applied loosely even to huge metropolitan areas; the precise meaning varies between countries and is not always a matter of legal definition. Usually, a "town" is thought of as larger than a village but smaller than a "city", though there are exceptions to this rule. The words "city" and "village" came into English from Latin via French. "Town" and "borough" (also "burrow", "burgh", "bury", etc.) are of native Germanic origin, from Old English burg, a fortified settlement, and tun, an enclosed piece of land.
City
A city is an urban area with a high population density and a particular administrative, legal, or historical status. Large industrialized cities generally have advanced systems for sanitation, utilities, land usage, housing, and transportation and more. This proximity greatly facilitates interaction between people and firms, benefiting both parties in the process. However, there is debate now whether the age of technology and instantaneous communication with the use of the Internet are making cities obsolete.
A big city, or metropolis, may have suburbs and regions. Such cities are usually associated with metropolitan areas and urban sprawl, creating large numbers of business commuters. Once a city sprawls far enough to reach another city, this region can be deemed a conurbation or megalopolis.
County
A county is a land area of local government within a country. A county may have cities and towns within its area.
Originally, in continental Europe, a county (comte', Grafschaft) was the land under the jurisdiction of a count (comte, Graf).
Counts are called earls in post-Celtic Britain and Ireland-the term is from Old Norse jarl and was introduced by the Vikings-but there is no correlation between counties and earldoms. Rather, county, from French comte', was simply used by the Normans after 1066 to replace the native English term scir -Modern English shire, as the Anglo-Saxon system of Shires was unique and thus hard for the Norman invaders to comprehend so they resorted to calling them Counties. A shire was an administrative division of an Anglo-Saxon kingdom (Wessex, Mercia, East Anglia, etc.), usually named after its administrative centre: for example, Gloucester, in Gloucestershire; Worcester, in Worcestershire; etc. or originate from these forms of names (e.g. Wiltshire derived from 'Wiltonshire' with Wilton as its old county town).
Thus, whereas the word comte' denoted a sovereign jurisdiction in the original French, the English county denotes a subdivision of a sovereign jurisdiction.