Which flower parts besides the ovary contribute to an apple or pear?

Apples and pears are classified as accessory fruits, a term used for fruits that incorporate floral parts beyond the ripened ovary in their development.12

In the case of both apples and pears, the primary non-ovary structure that contributes to the fruit is the hypanthium. The hypanthium is a floral tube or cup-shaped structure formed by the fusion of the bases of the sepals, petals, and stamens. In these pomes, this hypanthium becomes fleshy and adnate (fused) to the ovary, forming the bulk of the edible portion of the fruit. While the central part of the fruit represents the pericarp (the ripened ovary wall), the surrounding fleshy tissue that is typically consumed is derived from this modified floral tube.12