Old Money

[Trainspotter13]

Why was an old shilling called a bob and why was a sixpence called a tanner?

[Androcles]

From Wikipedia:

"A slang name for a shilling was a "bob" (which was invariant in the plural, as in "that cost me two bob"). In The Gambia, white people are called toubabs, which some claim derives from the fact that the price of a slave was two shillings,[citation needed] or from the colonial practice of paying locals two shillings for running errands[1]—though some consider this explanation implausible"

Apparently an early sixpence coin was designed by somebody called Tanner:

"Some of the issues of George II were designed by John Sigismund Tanner, and the denomination was known as a tanner right up to decimalisation. " http://www.coins-of-the-uk.co.uk/sixd.html

[DrFilth]

A pound comprised twenty Shillings, commonly called 'bob', which was a lovely old slang word. It was 'bob' irrespective of how many shillings there were: no-one ever said 'fifteen bobs' - it would have been said as 'fifteen bob'. The origin of the word 'bob' meaning Shilling is not known for sure, although the usage certainly dates back to the late 1700s. My favourite is suggested in Brewer's 1870 Dictionary of Phrase and Fable in that 'bob' could be derived from 'Bawbee', which was 16-19th century slang for a half-penny, in turn derived from: French 'bas billon', meaning debased copper money (coins were commonly cut to make change); and/or the Laird of Sillabawby, a 16th century mintmaster. Perhaps there is also a connection with the church or bell-ringing since 'bob' meant a set of changes rung on the bells. This would be consistent with one of the possible origins and associations of the root of the word Shilling, (from Proto-Germanic 'skell' meaning to sound or ring). Also perhaps a connection with a plumb-bob; (the association with another heavy piece of metal), made of lead and used to mark a vertical position in certain trades, notably masons. 'Bob a nob', in the early 1800s meant 'a shilling a head', when estimating costs of meals, etc. In the 18th century 'bobstick' was a shillings-worth of gin. In parts of the US 'bob' was slang used for the US dollar coin.