Uh, Uncle Cecil,
Isn’t “mill” spelled “mil”? (Link provided for the full story.)
http://www.straightdope.com/classics/a1_336b.html
Well, that’s the way I always heard it should be…
- Jinx
Nope. Cecil knows how to spell:
From here. A “mil” is 1/1000th of an inch, which is perhaps what you were thinking of.
Yep. QED is right. No actual US Mil coin. But some States have issued theirs.
Fun factoid:
As Cecil mentions, although the Federal government never minted a one-mill coin, they did mint a HALF CENT coin until 1857.
Why a half cent, you ask? Because 1/8 of a dollar is 12-and-a-half cents, so without a 1/2-cent coin you can’t make exactly 1/8 of a dollar in change. The American dollar was based on the Spanish Milled Dollar, which was worth 8 Reales (hence its nickname, the “piece of eight”). Therefore, it was a common practice to think of the American dollar as being “eight” of something, too. Stock prices continued to be traded in 1/8’s of a dollar until just a decade or two ago, and a quarter is still sometimes referred to as “two bits” because it’s 2/8 of a dollar.
Why a half cent, you ask?
I suspect the true reason the U.S. minted a half cent coin is because at the time a half cent was actually a reasonable amount to pay for some things and not due to your rather fanciful answer. Ever heard of penny candy? It actually cost a penny and that was in this century. It’s not hard to imagine some things cost half a cent in the 1800s.
If the bit was so important, I’d expect the U.S. would have minted a 12 1/2 cent coin.
England minted not only half pence but quarter pence coins simply because that’s what some things cost.
If the bit was so important, it would’ve been given a short, snappy name … like, oh, the bit, for instance.
I’ve heard the expression “four bits” for fifty cents as well as the more familiar “two-bits”. English speaking people do seem to like slang terms for money such as “fin”, “sawbuck”, “quid”, “bob”, and all the rest. I think the main reason “bit” is dying out is because the massive inflation we’ve seen since the word came into being, making the bit worth next to nothing. Time was when you could buy your lunch with two bits; nowadays, you’d need about forty-eight bits at the cafe across from my office, to get a sandwich and side and a drink.
And yet, when the computer age descended upon us, it was 8 bits that was settled on as the size of a byte. (Coincidence? Read the book!)
Was it a coincidence, or were they just using base 8? 
Uh, the term “bit” for computers is a contraction of the phrase “binary digit.” Coincidence? Yes. Read the book.