fiver

Short definition from Wiktionary

Noun

1. 1
   A banknote with a value of five units of currency.
2. 2
   The value in money that this represents.
3. 3
   A clenched fist.
4. 4
   A mathematical puzzle played on a 5 × 5 grid.
5. 5
   A Zaydi Shiite Muslim, who disagrees with the majority of Shiites on the identity of the Fifth Imam.
6. 6
   A person who gives five percent of their income or five hours a week of their time to charity (a reduction of ten percent tithing).
7. 7
   A Zaidi Shi'a Muslim.
8. 8
   A fan of the American science-fiction television series Babylon 5.