Margen
To a botanist, a berry is not "small fruit you eat by the handful". It is something very precise: a fleshy fruit that develops from a single flower with a single ovary and keeps its seeds inside the pulp.
By that yardstick, the banana passes with flying colours: one flower, one ovary, seeds inside (those little dark specks in the middle). Tomatoes, kiwis, grapes and aubergines are berries too — and even watermelons and oranges, which botanists class as modified berries with names of their own.
And the strawberry? It fails. The red, juicy part doesn't come from the ovary but from the flower's receptacle, which swells up like a cushion. The true fruits are the little yellow dots on the surface — achenes — each with its own seed inside. Technically, a strawberry is hundreds of tiny dry fruits glued to a swollen stem. Raspberries and blackberries are similar cases: clusters of small drupelets, not berries.
Next time someone asks for "berries", you have your answer ready: scientifically, the most famous one of all isn't even a fruit.