Endocarp
Endocarp is the inside of the fruit, particularly of the Valencia navel orange hesperidium. You may also refer to the endocarp as the carpel or pulp of the orange. The exocarp would be the outside skin or rind of the fruit.
Endocarp Media
Longitudinal section of a female flower of a squash plant (courgette), showing the ovary, ovules, pistil and petals
A schematic picture of an orange hesperidium
A segment of an orange that has been opened to show the pulp (juice vesicles) of the endocarp