Yes, in theory. However, if someone were to sell sour cherries, they would be labeled "sour cherries". In addition, the adjective 'sour' would be added to anything made with sour cherries (jam, juice, etc) (Sweet cherries are just referred to as 'cherries.")

There are many types of cherries. Some sweet commercial varieties of cherries are Bing and Rainer. There are also tart cherries such as Montmorency. Similar small bitter fruits called Chokecherries, and Pin Cherries also grow in North America.

The word can refer to a few things. It can refer to the fruit, or to an artificial flavour, which has little to nothing to do with the fruit, as it tastes nothing like the fruit. It also has a euphemistic meaning which I won't go into. In terms of sour cherries, I can only assume that 'cherry' refers to those fruit too, based on the name. I can't be completely sure as I've never seen or tasted one. We have cherry blossom trees here, and we do refer to their fruit as cherries, even though they are too small to bother eating.

Because in other languages such as Russian and Persian cherry and sour cherry are represented by different words. In Russian vishnia(sour cherry) chereshnia(cherry) in Persian albalo(sour cherry) gilas(cherry).... But in English it seems cherry refers to both....