decomposer
noun
de·com·pos·er ˌdē-kəm-ˈpō-zər 
: any of various organisms (such as many bacteria and fungi) that return constituents of organic substances to ecological cycles by feeding on and breaking down dead protoplasm compare consumer, producer sense 4
Example Sentences
Recent Examples on the Web Farmers in the region have been given a liquid decomposer to spray on their fields to break down stubble into organic fertilizer instead of burning, although the program is still considered in its trial phase. 
Washington Post, 15 Nov. 2021 As primary decomposers, mushrooms break down the organic matter of dead plants and animals. Popular Science, 13 May 2020 Scavengers scavenge, predators predate, decomposers decompose. New York Times, 22 Nov. 2019 But these decomposers just want the tasty packages of dead tissues and biominerals all to themselves. Anna K. Behrensmeyer, Smithsonian, 8 June 2019 Origins of a killer There are hundreds of species of chytrid fungi, and most of them are unobtrusive decomposers. Michael Greshko, National Geographic, 28 Mar. 2019 Atmospheric nitrogen gets churned through a series of chemical states by a diverse assortment of bacteria, plants and decomposers like fungi performing different reactions. Quanta Magazine, 20 Nov. 2018 Just as bodies are broken down in death by decomposers, every bit of them transformed into the matter that nourishes new life, so is the creative process a constant cycle. NBC News, 2 Apr. 2018 But snags are actually host to complex communities of decomposers — fungi, bacteria, bugs. Sarah Kaplan, Washington Post, 10 July 2017 See More
Washington Post, 15 Nov. 2021 As primary decomposers, mushrooms break down the organic matter of dead plants and animals. Popular Science, 13 May 2020 Scavengers scavenge, predators predate, decomposers decompose. New York Times, 22 Nov. 2019 But these decomposers just want the tasty packages of dead tissues and biominerals all to themselves. Anna K. Behrensmeyer, Smithsonian, 8 June 2019 Origins of a killer There are hundreds of species of chytrid fungi, and most of them are unobtrusive decomposers. Michael Greshko, National Geographic, 28 Mar. 2019 Atmospheric nitrogen gets churned through a series of chemical states by a diverse assortment of bacteria, plants and decomposers like fungi performing different reactions. Quanta Magazine, 20 Nov. 2018 Just as bodies are broken down in death by decomposers, every bit of them transformed into the matter that nourishes new life, so is the creative process a constant cycle. NBC News, 2 Apr. 2018 But snags are actually host to complex communities of decomposers — fungi, bacteria, bugs. Sarah Kaplan, Washington Post, 10 July 2017 See More Word History
First Known Use
1959, in the meaning defined above
Kids Definition
decomposer
noun
de·com·pos·er ˌdē-kəm-ˈpō-zər
: a living thing (as a bacterium, fungus, or insect) that feeds on and breaks down plant and animal matter into simpler parts or substances
Medical Definition
decomposer
noun
de·com·pos·er ˌdē-kəm-ˈpō-zər
: any of various organisms (as many bacteria and fungi) that return constituents of organic substances to ecological cycles by feeding on and breaking down dead protoplasm