if the entire fruit is fleshy, except for maybe a thin skin, the fruit is called a berry. a berry might contain one seed or many. grapes, avocados, and blueberries are berries. they all have a thin skin, but most of the fruit is fleshy. don't get confused by the name of fruits like strawberries, because actually they are "not" berries. the seeds are on the outside: on a real berry, the seed or seeds are "inside" the fruit.