A heterotroph has a range of meanings in biology:
- An organism which requires complex external sources for nutrition.
- An organism which uses organic products broken down by other organisms called autotrophs.
- An organism which can't synthesize its own nutrients.
- An organism dependent on preformed organic carbon produced by external sources.
In botany, a heterotroph is a plant which absorbs external organic matter for elements required for growth. The distinction is important, because alternative sources of growth materials are inorganic, which qualifies the functions of the plant's biology as a class. This is relevant because the requirements of plants for nutrition are extremely variable, and some biological functions may be based autotrophic or heterotrophic syntheses.