Telling whether the fruit is a berry or a drupe can be a little tricky. For example, some sources describe avocado as a drupe while others consider it a berry. To differentiate between a berry and a drupe, you should know the difference between them. A berry has an endocarp with a thickness less than 2 mm (3⁄32 in) thick. On the other hand, fruits that have a stony endocarp are known as drupes. Certain types of drupes can also identify whether a specific fruit is a berry or not.