Anyone in the wine business will be familiar with the term "brix," and many restaurant people will as well. But it's not in the common vernacular for most people.
Wikipedia provides a thorough definition. Here's the takeaway: In the wine industry, degrees Brix (or °Bx) is roughly speaking a measure of the amount of sugar in the juice of wine grapes. 26º Brix equals 26%, or 26 grams of sugar dissolved in 100 grams of water. Yeast ferments sugar at a rate of approximately 1% alcohol for every 1.8º Brix, so grapes with 26º Brix would yield dry wine with 14.5% alcohol, which is a typical alcohol percentage in good California wine.