a. [ Auto- + trophic. ] (Plant Physiol.) Capable of self-nourishment; requiring only minerals for growth; using carbonate or carbon dioxide as a source of carbon and simple inorganic nitrogen as a nitrogen source; -- said of all plants in which photosynthetic activity takes place, and certain bacteria. It is opposed to parasitism or saprophytism. [ Webster 1913 Suppl. + WordNet 1.5 ]