Berries are not actually what you think they are. Blackberries and raspberries are not berries at all, but things like bananas, pumpkins, avocados, and cucumbers all are. This is because a “berry” is a botanical definition for something that contains seeds on the inside that is surrounded by fruit, also known as pulp. Berries also have a special type of endocarp, which is the thin layer that directly covers the seeds. Berries have thin endocarps and fleshy pericarps, which is the outer layer.