It turns out berry is actually a botanical term, not a common English one. Blackberries, mulberries, and raspberries are not berries at all, but bananas, pumpkins, avocados, and cucumbers are. So what makes a berry?⁠ ⁠ Well, a berry has seeds and pulp that develop from the ovary of a flower. The pericarp of all fruit is actually subdivided into 3 layers. The exocarp is the skin of the fruit, and in berries, it’s often eaten but not always. The mesocarp is the part of the fruit we usually eat, like the white, yummy part of an apple, or the bulk of a plum, though in citrus fruits, the mesocarp is actually the white, sort of inner peel that we remove. Last is the endocarp, which is the closest layer that envelopes the seeds. In stone fruits, it’s a stone. In many fruits, it’s actually a membrane that we don’t really notice, often because it’s been bred to be thin, like in bananas. In citrus, the endocarp is actually the membrane that holds the juicy parts of the fruit, that is, the part y...