Are fruits always flesh part of fruits

Question

Are fruits always flesh part of “fruits”? Is edible part of the onion a fruit?

Answer 1

In some so-called fruits actual fruit is not flesh part. For instance, the flesh part of strawberry is not fruit. The fruits are small hard dots on the surface of strawberry.

One more instance: the flesh part of cashew is not the fruit. The fruit is nut. The edible part of onion is stem of the plant and not fruit.