Is anything actually gained from rigid definitions like this? People clearly use berry in a different way than botanists do.
If you're doing botany, you should probably use the latin term Fragaria instead of strawberry.
Edit: If you like this, you'll also find interesting that many nuts (hazlenuts, walnuts, Brazil nuts, pecans, almonds) are not nuts but seeds. One of the few actual nuts is a chestnut.
Do you mean they're edible?
The bit we eat is usually a seed or fruit - the shell encasing it is a nut. At least, that's what I understood.
When we say "a strawberry is not a berry" we're playing on the different meanings of the word berry. It's not a humourous pun, but I would still call it a pun.
Also, correcting people to say that bananas are berries doesn’t even acknowledge a second meaning of berry. It suggests the meaning they know of is wrong. I’m aware we’re talking about a technical meaning and a commonly-accepted meaning, but the assertion is suggesting the commonly-accepted meaning is completely invalid.
However, culinary definitions (where strawberries are berries and tomatoes are vegetables) are just as valid and not wrong because botanical definitions seemingly contradict them.
Bananas can both be berries and not berries at the same time and both definitions can be valid, what’s most useful then just depends on the context (and for most people most of the time that context is, by the way, a culinary one and not a botanical one).
For me its biological function is to be eaten, so I care more about where it goes than about where it comes.