Jonagold is an American apple, developed in the 1940s. As its name suggests, this is a cross between a Jonathan and a Golden Delicious. It is quite widely grown, and unusually for a Golden Delicious cross, is not limited to the warm apple regions, although it is not often found in the UK.
Jonagold is a large apple, and makes a substantial snack. If you are struggling to eat your 5 portions of fruit and veg per day, this can help !
The colouring is yellow of Golden Delicious, with large flushes of red. This is a crisp apple to bite into, with gleaming white flesh. The flavour is sweet but with a lot of acidity.
Jonagold's other parent, Jonathan, is an old (by American standards) variety which was discovered in the 1820s.
In the UK Jonagold sometimes appears in supermarkets in the spring packaged as "value" apples, often from Holland, and at a very low price.