The term compound fruit is not used in technical botanical writing, but is sometimes used when it is not clear which of several fruit types is involved. A compound fruit is "composed of two or more similar parts".
A compound fruit may be:
A pineapple is a multiple fruit
A tomato is a simple fruit derived from a compound ovary
Grapes grow in clusters, but are not compound fruits. Each grape is grown from one ovary in one flower, and each grape remains an independent fruit.