> It's because of the old apothocary's* symbol which always looked like a "3" to me, but is apparantly a lower case z. Of course, I don't know why they used that symbol, so it doesn't really answer your question. Probably something from Latin. Also, "oz" and "ounce" sound a bit alike (Not much, I know) so that might be part of the reason.
>
There is no z in Latin, but I can't really think of another reason.

> Anyway, I would like to close by saying that imperial measures rock.
>
> winter"chains, minims, perches, kilderkins, furlongs, acres..."mute
>
Yes, they do, but they're not very practical when you live in a civilization that uses a decimal number system.

> *The word "apothocary" is so much cooler than "chemist", don't you think?

Fuzz"Isn't it 'apothecary?'"pilz