Oxbridge is a portmanteau of Oxford and Cambridge, the two oldest, wealthiest, and most famous universities in the United Kingdom. The term is used to refer to them collectively, in contrast to other British universities, and more broadly to describe characteristics reminiscent of them, often with implications of superior social or intellectual status or elitism.
Although both universities were founded more than eight centuries ago, the term Oxbridge is relatively recent. In William Makepeace Thackeray's novel Pendennis, published in 1850, the main character attends the fictional Boniface College, Oxbridge. According to the Oxford English Dictionary, this is the first recorded instance of the word. Virginia Woolf used it, citing Thackeray, in her 1929 essay A Room of One's Own. The term was used in the Times Educational Supplement in 1957, and the following year in Universities Quarterly.
When expanded, the universities are almost always referred to as "Oxford and Cambridge", the order in which they were founded. A notable exception is Tokyo's Cambridge and Oxford Society; this probably arises from the fact that the Cambridge Club was founded there first, and also had more members than its Oxford counterpart when they amalgamated in 1905.
In addition to being a collective term, Oxbridge is often used as shorthand for characteristics the two institutions share:
They are the two oldest universities in continuous operation in the UK. Both were founded more than 800 years ago, and continued as England's only universities (barring short-lived foundations, such as those at Northampton and Durham) until the 19th century. Between them, they have educated a large number of Britain's most prominent scientists, writers, and politicians, as well as noted figures in many other fields.
Each has a similar collegiate structure, whereby the university is a cooperative of its constituent colleges, which are responsible for supervisions/tutorials (the principal undergraduate teaching method, unique to Oxbridge), accommodation and pastoral care.