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.
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.