Pound sterling (£)

Pre-1971: 20 shillings or 240 pence. Today: 100 new pence.

The £ is a stylised L, and the L is libra, the Roman pound — so the symbol on every British banknote is an abbreviation of a Latin word for a weight of silver. That is the whole system in miniature: £ for libra, s for solidus, d for denarius, a currency labelled throughout in a language nobody had spoken natively in Britain for a thousand years. The weight was once literal. A pound sterling meant a pound of sterling silver, struck into 240 pennies, which is why the pre-decimal pound divided the way it did. It is the oldest currency still in use, and the only part of the old system that survived 1971 unchanged in name.