Sometimes I wonder what makes a fruit a fruit.
From a culinary standpoint we consider sweet things like peaches and plums to be fruit and savory foods like peas and carrots to be vegetables. But what if a fruit is sour like a cherry? It’s still a fruit, right?
I remember reading once that tomatoes are fruit because they have seeds inside, and it’s true they are fruit but that’s not the only reason. Strawberries are fruit as well but their seeds are on the outside.
Botanically speaking fruit are produced at the flower of the plant so apples, plums, tomatillos or any other plant that produces a flower and a subsequent seed holding/containing product is a fruit. That includes cucumbers, peppers and yes, tomatoes.
What about peas and beans, you ask? Well they are called legumes and technically the pod or she’ll is the fruit and the seed is found inside, but we classify the entirety as a legume.
Vegetables are the leaves (lettuce), roots (carrots), tubers (potatoes) and stalks (celery) of plants. Some vegetables are the flowers of plants (broccoli).
Sometimes a plant can be a vegetable in its early stages (like the flowers of zucchini or bean sprouts) and still produce an edible fruit.
Clear as mud?
Gardeninggrrl 
I do find this confusing – not your explanation, which is very clear, but the rules behind the classifications. My sweetheart, who knows about these things, seems to correct my ‘fruit’ to ‘vegetable’ and vice versa fairly often! Avocado, for example?