in·di·ca·tor / ˈindiˌkātər/ • n. 1. a thing, esp. a trend or fact, that indicates the state or level of something: car ownership is frequently used as an indicator of affluence.2. a device providing specific information on the state or condition of something, in particular: ∎  a gauge or meter of a specified kind: a speed indicator.3. Chem. a compound that changes color at a specific pH value or in the presence of a particular substance and can be used to monitor acidity, alkalinity, or the progress of a reaction.4. (also indicator species) an animal or plant species that can be used to infer conditions in a particular habitat.

indicator
1. A bit or bit configuration that may be inspected to determine a status or condition. Examples are an overflow bit, a device status, any portion of the program status word. See also qualifier register.

2. A visual, sometimes aural, indication of the occurrence of a specific status or condition, e.g. system running (halted), undefined instruction.

indicator A quantitative measure which reflects change in some aspect of the economy or of society—such as mortality rates, measures of job segregation, or the retail price index. In the 1960s and 1970s, effort was invested in developing systems of social indicators, to monitor and evaluate social policy.

indicator In chemistry, substance used to indicate acidity or alkalinity. It does this usually by a change of colour. Indicators, such as the dye litmus, can detect a change of pH, which measures a solution's acidity (litmus turns red) or alkalinity (turns blue). Universal indicator (liquid or paper) undergoes a spectral range of colour changes from pH 1 to 13.

Indicator (honeyguides) See INDICATORIDAE.