The term horticulture comes from two Latin words namely: hortus (garden) and colere (to cultivate or tend). Simply horticulture means "tending a garden" or just gardening.
As a field of study, horticulture is the science, art, and business of growing and marketing fruits, vegetables, flowers, and ornamental plants. The crops studied in horticulture are those that require more intense and constant care. These include but not limited to ornamental plants, cash crops and hobby plants. Therefore a crop is considered horticultural depending on the purpose that they are grown. For example, wheat (Triticum aestivum L.) is a low-input crop and is traditionally grown for their grains on big acres of fields - it is considered an agronomic crop. When wheat is grown as wheatgrass for their wheat juice (like the green stuff you get from Jamba Juice) then it is considered a horticultural crop.
Horticulture involves two main types of plants: Plants that are grown for food are called edibles while plants grown for aesthetics are ornamentals. There are several number of sciences under these two categories which I will discuss as we deal with them in the future.