I always assumed that the word re, as in "re your email dated 6 March, I thank you very much for the offer of $1,000,000 in cash, but I shan’t be taking it up" was short for "regarding". Well, not at all! According to the Concise Oxford English Dictionary:

re, prep. in the matter of (as the first word of a heading, esp. of a legal document). 2 colloq. about, concerning. [Latin, ablative of res ‘thing’]

The things you learn while trying to put down slightly dodgy words during a game of Scrabble.