The word bit is a colloquial expression referring to specific coins in various coinages throughout the world.
[1][2] With the adoption of the decimal U.S. currency in 1794, there was no longer a U.S. coin worth $1⁄8, but "two bits" remained in the language with the meaning of $1⁄4.
Robert Louis Stevenson describes his experience with bits in Across the Plains, (1892) p. 144:[5] In the Pacific States they have made a bolder push for complexity, and settle their affairs by a coin that no longer exists – the bit, or old Mexican real.
But if you have not, and lay down a quarter, the bar-keeper or shopman calmly tenders you a dime by way of change; and thus you have paid what is called a long bit, and lost two and a half cents, or even, by comparison with a short bit, five cents.
Roger Miller's song "King of the Road" features the lines: Ah, but two hours of pushin' broom buys an / Eight by twelve four-bit room referring to signs stating "Rooms to let, 50¢."
In Britain, Ireland and parts of the former British Empire, where before decimalisation a British-style currency of "pounds, shillings and pence" was in use, the word "bit" was applied colloquially to any of a range of low-denomination coins.
The historic American adjective "two-bit" (to describe something worthless or insignificant) has a British equivalent in "tuppenny-ha'penny" – literally, worth two and a half (old) pence.