English dictionary definition of decomposer. An organism, often a bacterium or fungus, that feeds on and breaks down dead plant or animal matter, thus making organic nutrients available to the.

A decomposer is an organism that decomposes, or breaks down, organic material such as the remains of dead organisms. Decomposers include bacteria and fungi.
Their role is ecologically essential as they recycle the nutrients through a natural biological process ( decomposition ). A decomposer is defined as an organism that decomposes or breaks down the organic material including the remains of dead organisms. The decomposers are included bacteria and fungi. Like herbivores and predators, decomposers are heterotrophic, meaning that they use organic substrates to get their energy, carbon and nutrients for growth and development.