indicator

indicator is a   Noun

Definition:

[1] One who, or that which, shows or points out; as, a fare indicator in a street car.

[2] A pressure gauge; a water gauge, as for a steam boiler; an apparatus or instrument for showing the working of a machine or moving part; as:

[3] A telltale connected with a hoisting machine, to show, at the surface, the position of the cage in the shaft of a mine, etc.

[4] The part of an instrument by which an effect is indicated, as an index or pointer.

[5] Any bird of the genus Indicator and allied genera. See Honey guide, under Honey.

[6] That which indicates the condition of acidity, alkalinity, or the deficiency, excess, or sufficiency of a standard reagent, by causing an appearance, disappearance, or change of color, as in titration or volumetric analysis.

Synonyms: