Bananas are berries. Strawberries are not.
Botany disagrees with the supermarket.
A true berry, botanically, comes from a single flower with one ovary and has seeds embedded in its flesh. Bananas qualify. So do watermelons, tomatoes and avocados. Strawberries — an "accessory fruit" formed from many ovaries — do not.
Editor's Note
We rarely notice how many of our categories were invented by someone else.