What kinda fruit is this?

Question

it is small but not a plum same color. it is a tree not a bush there is one pit and when you eat the yellow inside there is a pit and it is very sour. please help

Answer 1

It could be a damson. They are smaller than a plum, the fruit is tart. Fruit makes very good jelly.

Answer 2

Are you sure it's not a wild plum, it sounds just like a wild plum.

Answer 3

Probably    Persimmons