The shilling was a British coin, in circulation between 1707 and the decimalisation of the currency in 1971. There were twenty shillings to the pound, and 12 old pennies to the shilling.
Up until 1947, the coin was made wholly, or partially, of silver, but from 1947 onwards it was made of cupro-nickel. The informal term for a shilling was a bob (as in, "that cost me ten bob").
A shilling in today's money is the equivalent of five pence.
Between 1849 and 1967, there was also a two-shilling coin in existence. This was known either as a two-shilling piece, a two-bob bit, or a florin.