noun Biology, Biochemistry.
- the synthesis of organic compounds within an organism, with chemical reactions providing the energy source.
- the formation of organic material by certain bacteria using energy derived from simple chemical reactions
- The formation of organic compounds using the energy released from chemical reactions instead of the energy of sunlight. Bacteria living in aphotic areas of the ocean are able to survive by chemosynthesis. They use energy derived from the oxidation of inorganic chemicals, such as sulfur released from deep hydrothermal vents, to produce their food. Compare photosynthesis.