The fleshy or dry ripened ovary of a plant contains seeds inside it, which is called a fruit.
There are two main types of fruits depending on the part of flower that fruits develop: True fruits and False fruits.
True fruits: The fruits that develop from the ovary of the flower are known as true flowers. Mango, coconut, etc. are true fruits.
False fruits: The fruits that develop from other parts of the flower like thalamus, inflorescence, calyx and not only from the ovary of the flower are known as false flowers. Apple, strawberry, etc. are false fruits.
Apple:
Apple is formed from the thalamus of the flower apart from the ovary.