[ in-di-key-ter ]
See synonyms for: indicatorindicators on

  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: The fuel indicator was pointing to empty.Move the indicator to the edge of the browser and drag to resize the window.

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

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

  3. Chemistry.

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

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

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

Origin of indicator

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

Words Nearby indicator Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2024

How to use indicator in a sentence

British Dictionary definitions for indicator


/ (ˈɪndɪˌkeɪtə) /

  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

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

    • 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

    • (as modifier): indicator light

  2. 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

  3. 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

  4. chem

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

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

  5. Also called: indicator species ecology

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

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

Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Scientific definitions for indicator


[ ĭndĭ-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.

The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.