indicator (redirected from biologic indicator)

indicator

1. a device to attract attention, such as the pointer of a gauge or a warning lamp

2. an instrument that displays certain operating conditions in a machine, such as a gauge showing temperature, speed, pressure, etc.

3. a device for indicating that a motor vehicle is about to turn left or right, esp two pairs of lights that flash when operated or a pair of trafficators

4. a delicate measuring instrument used to determine small differences in the height of mechanical components. It consists of a spring-loaded plunger that operates a pointer moving over a circular scale

5. Chem

a. a substance used in titrations to indicate the completion of a chemical reaction, usually by a change of colour

b. a substance, such as litmus, that indicates the presence of an acid or alkali

6. Ecology

a. a plant or animal species that thrives only under particular environmental conditions and therefore indicates these conditions where it is found

b. a species of plant or animal whose well-being confirms the well-being of other species in the area

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indicator [′in·də‚kād·ər]

(chemistry)

chemical indicator

(computer science)

A device announcing an error or failure.

(electronics)

A cathode-ray tube or other device that presents information transmitted or relayed from some other source, as from a radar receiver.

(engineering)

An instrument for obtaining a diagram of the pressure-volume changes in a running positive-displacement engine, compressor, or pump cylinder during the working cycle.

(mathematics)

Euler's phi function