The botanical definition of a berry is a fleshy fruit produced from a single ovary. Grapes are an example. The berry is the most common type of fleshy fruit in which the entire ovary wall ripens into an edible pericarp. They may have one or more carpels with a thin covering and fleshy interiors. The seeds are usually embedded in the flesh of the ovary (there are some non-fleshy exceptions, such as peppers). A plant that bears berries is said to be bacciferous or baccate (a fruit that resembles a berry, whether it actually is a berry or not, can also be called "baccate").

In everyday English, "berry" is a term for any small edible fruit. These "berries" are usually juicy, round or semi-oblong, brightly coloured, sweet or sour, and do not have a stone or pit, although many seeds may be present.

Many berries, such as the tomato, are edible, but others in the same family, such as the fruits of the deadly nightshade (Atropa belladonna) and the fruits of the potato (Solanum tuberosum) are poisonous to humans. Some berries, such as Capsicum, have space rather than pulp around their seeds.