The term flora refers to the set of plants, native or introduced, from a geographic region,[1]​ from a specific geological period,[2]​ or from a specific ecosystem. The term comes from Latin in allusion to the Roman goddess of flowers, Flora "Flora (mythology)").[3] Flora defines the species of plants and their number, while the term vegetation refers to their geographical distribution. Therefore, the flora, depending on the climate and other environmental factors, determines the vegetation.

The sciences that study flora are geobotany, synecology, phytocenosis and paleobiogeography.[4]​.

The term flora "Flora (publication)") is also used to refer to treatises or books that describe the plants of a region, geological period, or ecosystem.[1]​.

Vulgarly, the term intestinal flora is used to refer to the set of microorganisms and bacteria that live in the intestines of animals, but the term has no relation to the plant flora and is not scientifically rigorous.[5]​.

Plants are grouped into floras that are based on regions, periods, special environments or climates. Regions can be geographically distinct habitats, such as mountains or plains. They can refer to the plant life of a historical era as fossil flora and can be subdivided into special environments:.