I’ll have to agree with Robin on this one; one should never confuse a wine being tannic and a dry wine.
As I think about it more, I don’t think there is a precise definition for a “dry wine”. Even though a majority of the population might consider wines with a so-and-so RS percentage “dry” or so-and so RS percentage “sweet”. Everyone has their own personal threshold for level of sweetness (or dryness). BTW I think Robin’s definition; dry is not sweet, fits the bill nicely.
having just returned from canada - which publishes a sugar code for each wine i discovered some interesting things.
two red wines - yellow tail and calatera are a sugar code 1 - definitly NOT dry. some of the niagara wines labeled as dry rieslings are a 0 and some are 1. there is at least one 'off dry' riesling (according to the label) which is a 2. i wish we could have something like that here.
Jackson's 'Wine Science' defines dry as 'having no perceptible sweetness,' which is a useful way of looking at it.
Other than this pragmatic way of using the word, there are at least two others: in my experience winemakers use 'dry' to mean 'no fermentable sugars' (ie <2g/L or so), and marketers use it to mean 'less sweet than similar examples, therefore sophisticated, so buy some.'