- any substance, such as manure or a mixture of nitrates, added to soil or water to increase its productivity
- an object or organism such as an insect that fertilizes an animal or plant
WordReference Random House Learner's Dictionary of American English © 2019
- Agricultureany substance used to fertilize the soil.
- any substance used to fertilize the soil, esp. a commercial or chemical manure.
- a person, insect, etc., that fertilizes an animal or plant:Bees are fertilizers of flowers.
- fertilize + -er1 1655–65