The word borough derives from common Proto-Germanic *burgz, meaning "fort": compare with bury, burgh and brough (England), burgh (Scotland), Burg (Germany), borg (Scandinavia), burcht, burg (Dutch), boarch (West Frisian), and the Germanic borrowing present in neighbouring Indo-European languages such as borgo (Italian), bourg (French), burgo (Spanish and Portuguese), burg (Romanian), purg (Kajkavian), durgo (দুর্গ, Bengali), durg (दर्ग, Hindi) and arg (ارگ, Persian). The incidence of these words as suffixes to place names (for example, Aldeburgh, Bamburgh, Tilbury, Tilburg, Strasbourg (Strossburi in the local dialect), Luxembourg, Edinburgh, Grundisburgh, 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 particular 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 world. Often, a borough is a single town with its own local government. However, in some cities it is a subdivision of the city (for example, New York City, London, 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. In other places, such as the U.S. state of Alaska, borough designates a whole region; Alaska's largest borough, the North Slope Borough, is comparable in area to the entire United Kingdom, although its population is less than that of Swanage on England's south coast with around 9,600 inhabitants. In Australia, a borough was once a self-governing small town, but this designation has all but vanished, except for the only remaining borough in the country, which is the 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 province of Quebec and formerly in Ontario, in some states of the United States, in Israel, formerly in New Zealand and only one left in Australia.
The word borough derives from the Old English word burh, meaning a fortified settlement. Other English derivatives of burh include bury, brough and burgh. There are obvious cognates in other Indo-European languages. For example; burgh in Scots and Middle English; burg in German and Old English, borg in Scandinavian languages; parcus in Latin and pyrgos in Greek, برج (borj) in Persian.
A number of other European languages have cognate words that were borrowed from the Germanic languages during the Middle Ages, including brog in Irish, bwr or bwrc, meaning "wall, rampart" in Welsh, bourg in French, burg in Catalan (in Catalonia there is a town named Burg), borgo in Italian, and burgo in Portuguese and Spanish (hence the place-name Burgos).
The 'burg' element, which means "castle" or "fortress", is often confused with 'berg' meaning "hill" or "mountain" (c.f. iceberg, inselberg). Hence the 'berg' element in Bergen or Heidelberg relates to a hill, rather than a fort. In some cases, the 'berg' element in place names has converged towards burg/borough; for instance Farnborough, from fernaberga (fern-hill).