A substance employed to produce a chemical reaction so as to detect, measure, produce, etc., other substances.
A chemical substance which reacts with another substance, especially one which is used to detect the presence of the second substance.
A substance used to produce a chemical reaction to detect, measure, or produce other substances. For example, one reagent (Ilosvay reagent) is used to test for the presence of nitrites: several substances are mixed together to produce a sediment that is then dissolved in acetic acid. It is then combined with the substance suspected of containing nitrites. If present, the nitrites will cause the solution to turn red when heated.
The term is commonly used to describe any chemical component involved in a chemical reaction. It often refers to a specific chemical or a combination of chemicals employed in chemical analysis or for identifying biological substances.
A substance that takes part in a chemical reaction or is used to identify or measure another substance through chemical or microscopic methods.