Ameliorant is defined as something that improves the condition of someone or something.
(noun)An example of an ameliorant is aloe vera when used on sunburned skin.
The definition of an ameliorant is chemical that is applied to improve the quality of the soil and thereby improve plant growth.
(noun)An example of ameliorant is the product Miracle-Gro.
See ameliorant in Webster's New World College Dictionary
noun