A borough is an administrative division in many countries. It is a kind of local government.
The term borough can means a self-governing township.
In medieval times, boroughs were settlements with some self-government. Boroughs were particularly common in England, Germany and Scotland. In medieval England, boroughs had also the right to elect members of parliament. (The Borough in Southwark, London is thought to have been the original 'borough' of which all others come from.)