Fiver/ˈfaɪvər/ Definition 1 of 1Pro Tip 1/3Currency Specific The value of a 'fiver' depends on the country: £5 in the UK, €5 in the eurozone, etc. In the UK, a fiver gets you a sandwich. Pro Tip 2/3Informal Term 'Fiver' is casual language, more common in speech than writing, and used in informal settings. Got a fiver I can borrow for the vending machine? Pro Tip 3/3Physical Money While 'fiver' refers to both notes and coins, it's most often used for banknotes. I found a fiver in my jacket pocket!