Definition of indicator
- n. - One who, or that which, shows or points out; as, a fare
indicator in a street car.
- n. - 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
- n. - An instrument which draws a diagram showing the varying
pressure in the cylinder of an engine or pump at every point of the
stroke. It consists of a small cylinder communicating with the engine
cylinder and fitted with a piston which the varying pressure drives
upward more or less against the resistance of a spring. A lever imparts
motion to a pencil which traces the diagram on a card wrapped around a
vertical drum which is turned back and forth by a string connected with
the piston rod of the engine. See Indicator card (below).
- n. - A telltale connected with a hoisting machine, to show,
at the surface, the position of the cage in the shaft of a mine, etc.
- n. - The part of an instrument by which an effect is
indicated, as an index or pointer.
- n. - Any bird of the genus Indicator and allied genera. See
Honey guide, under Honey.
- n. - 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.