Fruit is an old French word that is derived from the Latin root, fructus, which roughly means a profit or income. To most people today, fruits are edible produce that we buy in the grocery store, but to a botanists the word has a slightly narrower meaning. In scientific terms, a fruit is the seed-bearing part of the plant that is formed after fertilization occurs.
Before a fruit can be formed, the flowers must bloom so the male and female parts can develop and produce pollen and receptive ovules. Within the flower, pollen is produced in the stamens, while the female ovules form inside a pistil. In most cases the male stamens and female pistil occur within the same flower, but there are times where flowers with develop into male or female units.
Once the flowers open, a mechanism is needed to transport the pollen from the stamen to the pistil. In most flowering plants the pollen must travel to a different plant of the same species in order for fertilization to occur. This process is called cross-fertilization and it ensures that the genetic offspring are not completely identical to the parent. Insects and the wind are the two most common means of transporting pollen to another plant, but flowers can also be pollinated by bats, birds, spiders, butterflies, moths or water. Self-pollination is rare but does occur in a few plants.
Once the pollen arrives at the top of the pistil, where the stigma is located, it needs to travel down the pollen tube to the base of the pistil, where it can find a receptive ovule; this is the female genetic material found inside the ovary. Once the pollen finds the ovule, the male and female genetic material combines to form an embryo, which will eventually develop into a seed.
Once the embryo is formed, the cells of the embryo will start to grow in a normal method. After the embryo grows beyond its two-cell stage it is referred to a zygote. As time goes on the zygote will grow larger. Eventually cell differentiation begins and the zygote will begin to change into a seed.
Once the zygote starts to grow, the ovary will begin developing into a fruit and the ovules will begin to form seeds.. The outside wall of the ovary and pistil becomes the skin of the fruit, or in some cases like the apple and pear, there develops a fleshy and edible material outside the ovary wall which will become the edible part of the fruit. This fleshy material is then covered by an outer covering that is derived from the petals, sepals and bracts. In either case the fruit will grow as long as the plant does, but eventually it will fall from the tree when the plant goes dormant for the winter.