Wiki article on this topic:
A berry is a small, pulpy, and often edible fruit. Typically, berries are juicy, rounded, brightly colored, sweet or sour, and do not have a stone or pit, although many pips or seeds may be present. Common examples are strawberries, raspberries, blueberries, blackberries, red currants, white currants and blackcurrants. In Britain, soft fruit is a horticultural term for such fruits.
The scientific usage of the term "berry" differs from common usage. In scientific terminology, a berry is a fruit produced from the ovary of a single flower in which the outer layer of the ovary wall develops into an edible fleshy portion. The definition includes many fruits that are not commonly known as berries, such as grapes, tomatoes, cucumbers, eggplants, bananas, and chili peppers. Fruits excluded by the botanical definition include strawberries, raspberries, and blackberries, which are aggregate fruits; and mulberries, which are multiple fruits. A plant bearing berries is said to be bacciferous or baccate.
While many berries are edible, some are poisonous to humans, such as deadly nightshade and pokeweed. Others, such as the white mulberry, red mulberry, and elderberry, are poisonous when unripe, but are edible when ripe.
Berries are eaten worldwide and often used in jams, preserves, cakes, or pies. Some berries are commercially important. The berry industry varies from country to country as do types of berries cultivated or growing in the wild. Some berries such as raspberries and strawberries have been bred for hundreds of years and are distinct from their wild counterparts, while other berries, such as lingonberries and cloudberries, grow almost exclusively in the wild.
Berries have been valuable as a food source for humans since before the start of agriculture, and remain among the primary food sources of other primates. They were a seasonal staple for early hunter-gatherers for thousands of years, and wild berry gathering remains a popular activity in Europe and North America today. In time, humans learned to store berries so that they could be used in the winter. They may be made into fruit preserves, and among Native Americans, mixed with meat and fats as pemmican.