indicator

American  

[in-di-key-ter] / ˈɪn dɪˌkeɪ tər /

noun

1. a person or thing that indicates, signals, or points out.

2. a pointing or directing mechanism, as a pointer on the dial of an instrument to show pressure, temperature, speed, volume, etc., or a moveable icon in the graphical user interface of a computer or other device: Move the indicator to the edge of the browser and drag to resize the window.

   The fuel indicator was pointing to empty.

   Move the indicator to the edge of the browser and drag to resize the window.

3. an instrument that indicates the condition of a machine or the like.

4. an instrument for measuring and recording variations of pressure in the cylinder of an engine.

5. Chemistry.

   1. a substance, as litmus, that indicates the presence or concentration of a certain constituent.

   2. a substance often used in a titration to indicate the point at which the reaction is complete.

6. Ecology. a plant, animal, or species that indicates, by its presence in a given area, the existence of certain environmental conditions.

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indicator British  

/ ˈɪndɪˌkeɪtə /

noun

1. something that provides an indication, esp of trends See economic indicator

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

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

4. 1. a device that records or registers something, such as the movements of a lift, or that shows information, such as arrival and departure times of trains

   2. ( as modifier )

      indicator light

5. Also called: blinker.  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

6. Also called: dial gauge.  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

7. chem

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

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

8. Also called: indicator species.  ecology

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

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

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indicator Scientific  

/ ĭn′dĭ-kā′tər /

1. A chemical compound that changes color and structure when exposed to certain conditions and is therefore useful for chemical tests. Litmus, for example, is an indicator that becomes red in the presence of acids and blue in the presence of bases.

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Etymology

Origin of indicator

First recorded in 1660–70; from Late Latin indicātor, equivalent to Latin indicā(re) “to make known, point out” + -tor; indicate, -tor

Explanation

If you're familiar with the verb to "indicate," then indicator should be no problem. An indicator points to, suggests, or shows something. The arrow on a street sign is an indicator telling you which way to go. "It's not the heat, it's the humidity!" In other words, temperature is only one indicator of how it feels outside. Air-pressure, humidity, wind-chill, and cloud cover are other important indicators of weather conditions. You might hear a lot from newscasters about "economic indicators." These are figures, such as the rate of unemployment or inflation, that indicate where we're headed economically. Good or bad, we need reliable indicators if we're going to recover economically. Not all the indicators say the same thing: some say we're going to be OK sooner than others.

Example Sentences

Kizemchuk sees the Arms Index as an indicator of whether a rally is being supported by “real buying” or by short-term flows like short covering.

From MarketWatch • Apr. 11, 2026

The Relative Niño 3.4 Index is an indicator of central tropical Pacific El Niño conditions.

From BBC • Apr. 10, 2026

It does not disclose details regarding its adhesives and wetness indicator, however, according to Consumer Report’s evaluation.

From Los Angeles Times • Apr. 10, 2026

Saudi’s monthly crude pricing is closely watched by traders as a key indicator of the kingdom’s outlook on regional demand.

From The Wall Street Journal • Apr. 7, 2026

That was always a good indicator of how truthful they were.

From "City Spies" by James Ponti

Related Words

• barometer
• gauge
• index
• signal
• symbol