Quick answers at PeterWhieldon.co.uk
Acidity can be detected ‘on the nose’ and ‘on the taste’.
A mouth watering and refreshing example would be referring to a tartaric presence giving the wine crispness and zing!
It is important that the wine has a fine balance of tartaric and citric acids as the esters of both contribute to the overall bouquet of that wine. It is equally important that the balance is right as it acts as a preservative as well.
Another reference to acidity is ‘bite’ meaning the wine has a very noticeable taste, usually from the acidity or having a tannic (tannins) presence.