The key difference between ovary and ovule is that the ovary is a part of the female reproductive structure that develops into a fruit of flowering plants while the ovule is a structure that develops into a seed of seed plants.
The flower is the reproductive structure of flowering plants. Some flowers are perfect while some are imperfect flowers. Perfect flowers contain both the male and female reproductive parts as androecium and gynoecium respectively. Gynoecium has three main components namely stigma, style and ovary. Accordingly, the ovary is the structure that contains ovules. We can find it at the base of the gynoecium. Thus, ovules are the structures that bear female reproductive cells or the egg cells. Ovary surrounds the ovules in flower. One ovary may contain many ovules but, one ovule often contains one egg cell (female gamete). After fertilization, ovary and ovule develop into different structures of a fruit.
