quid = one pound (£1) or a number of pounds sterling. Plural uses singular form, eg., 'Fifteen quid is all I want for it..', or 'I won five hundred quid on the horses yesterday..'. The slang money expression 'quid' seems first to have appeared in late 1600s England, derived from Latin (quid meaning 'what', as in 'quid pro quo' - 'something for something else'). Other intriguing possible origins/influences include a suggested connection with the highly secretive Quidhampton banknote paper-mill, and the term quid as applied (ack D Murray) to chewing tobacco, which are explained in more detail under quid in the cliches, words and slang page.