Pardon my ignorance, Kermit, but what is a "tenth?"

I really enjoy Kermit Lynch's newsletters, and have been turned on to many enjoyable wines by this retailer.
Often, he will offer wines in regular bottles, magnums, and tenths. I have seen 375s before, but I've yet to run into a tenth.
So my question is, a tenth of what? A liter? That doesn't seem like very much wine.

Can someone shed some light on this mystery for me?

Prior to the metric system, American wines were sold in "Fifths", which id 1/5 gallon or 25.6 oz. 750 mls = 25.4 oz. I wouls assume a "Tenth" is a half bottle using the older designation, or 12.8 oz. (1 gallon = 128 oz.

Howie has it right, John. Usually when Lynch lists a tenth, he also offers a fifth.

thanks - so a tenth would equate more or less to a 375.
Give me the metric system - I wonder why he clings to the old ways.

thanks - so a tenth would equate more or less to a 375.
Give me the metric system - I wonder why he clings to the old ways.

Perhaps he's selling old bottles - pre-metric?

Or maybe Kermit isn't getting any younger