(Usually followed by ‘species’), any plant or taxon that is thought to show a condition of the environment (e.g. a copper indicator or an indicator of human disturbance).
Usually refers to a pH indicator. Various dyes change color at a specific degree of acidity or alkalinity, and this color change is used as an indicator of pH.
A substance which shows something, e.g. a substance secreted in body fluids which shows which blood group a person belongs to.
Something that serves as a warning or guide.
Substance (e.g., paper, tablet, tape) used to test for a particular reaction because of a predictable, easy-to-detect change; for example, litmus paper turns pink on exposure to an acid.
Defined by the Joint Commission on Accreditation of Healthcare Organizations (JCAHO) as “a tool used to measure, over time, the performance of functions, processes, and outcomes of an organizations.”
In chemical analysis, a substance that can be used to determine pH. In a more general sense, any substance that can be used to determine the completeness of a chemical reaction, as in volumetric analysis. Its uses include (1) in the titration of ammonia and other weak bases; (2) in Topfer’s reagent, for determining free acid in gastric juice; and (3) in the titration of weak acids and determination of combined acid in gastric juice.