## Friday, October 07, 2011

### The solidus mark

The solidus was a Roman coin but it is also the name for a punctuation symbol that looks exactly like a slash. The Wikipedia article explains that '2 pounds, 10 shillings, and 6 pence' was written as £2 ⁄ 10 ⁄ 6 (as an alternative to '£2 10s. 6d.') and '10 shillings' would often be written as 10 ⁄ -.

The / has the form it does because it is an abbreviation for “Long S” sometimes known as the integral symbol. It is also called a shilling mark.

So we have a single-stroke symbol that is an textual abbreviation for another single-stroke symbol. The abbreviation has two names, both derived from denominations of coins.