The quid is the common slang term for the pound sterling, which is the official currency of the United Kingdom (U.K.) and its dependencies. According to its issuance when it was introduced in 1489 during the reign of King Henry VII, it was known as the sovereign.

The word quid is said to have first come into use in the late 17th century, deriving from the Latin term quid pro quo meaning something for something. It has become so common in everyday British culture that people are likely to say 'a quid', 'two quid' or 'fifty quid' when talking about figures in pounds instead of the numbers alone.

One pound sterling is equal to 100 pence, and as such, the quid is considered a unit of currency rather than a coin. In the 21st century, the quid has become a more abstract term to signify the pound sterling in the UK, with physical money now issued in the form of coins ranging from the one penny coin, up to two pound coins.

A person can carry out a wide range of activities and transactions with their quid, from buying goods and services to transferring money to a foreign country. Quid can also be used to refer to the British pound (GBP) when trading foreign currencies. In modern economies, the quid is still one of the most valuable and widely accepted currencies in the world.

In addition to its ever-evolving usage, the quid has become an integral part of the British national identity. As a result, it is celebrated in popular culture and media, ranging from literature to television shows to music. In the financial world, the quid still remains relevant and is a symbol of British prosperity and stability.