INDICATOR
indicator
(noun) a device for showing the operating condition of some system
index, index number, indicant, indicator
(noun) a number or ratio (a value on a scale of measurement) derived from a series of observed facts; can reveal relative changes as a function of time
indicator
(noun) a signal for attracting attention
indicator
(noun) (chemistry) a substance that changes color to indicate the presence of some ion or substance; can be used to indicate the completion of a chemical reaction or (in medicine) to test for a particular reaction
Source: WordNet® 3.1
Etymology
Noun
indicator (plural indicators)
A pointer or index that indicates something.
A meter or gauge.
The needle or dial on such a meter.
(chemistry) Any of many substances, such as litmus, used to indicate the concentration of a substance, or the degree of a reaction.
(ecology) A plant or animal whose presence is indicative of some specific environment.
(economics) A measure, such as unemployment rate, which can be used to predict economic trends.
(UK, Australia, automotive) A turn signal; each of the flashing lights on each side of a vehicle which indicate a turn is being made to left or right, or a lane change etc.
A bird, the honeyguide.
Synonyms
• blinker (informal), directional, directional signal, trafficator, turn indicator, turn signal (US)
Anagrams
• anidrotic, cardiotin
Source: Wiktionary
In"di*ca`tor, n. Etym: [L.: cf. F. indicateur.]
1. One who, or that which, shows or points out; as, a fare indicator
in a street car.
2. (Mach.)
Definition: 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:
(a) (Steam Engine) 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).
(b) A telltale connected with a hoisting machine, to show, at the
surface, the position of the cage in the shaft of a mine, etc.
3. (Mech.)
Definition: The part of an instrument by which an effect is indicated, as
an index or pointer.
4. (Zoöl.)
Definition: Any bird of the genus Indicator and allied genera. See Honey
guide, under Honey.
5. (Chem.)
Definition: 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.
Note: The common indicators are limits, tropæolin, phenol phthalein,
potassic permanganate, etc. Indicator card, the figure drawn by an
engine indicator, by means of which the working of the engine can be
investigated and its power calculated. The Illustration shows one
form of indicator card, from a steam engine, together with scales by
which the pressure of the steam above or below that of the
atmosphere, corresponding to any position of the engine piston in its
stroke, can be measured. Called also indicator diagram.
– Indicator telegraph, a telegraph in which the signals are the
deflections of a magnetic needle, as in the trans-Atlantic system.
Source: Webster’s Unabridged Dictionary 1913 Edition