indicator

noun

in·​di·​ca·​tor ˈin-də-ˌkā-tər 

1

: one that indicates: such as

a

: an index hand (as on a dial) : pointer

b(1)

: gauge sense 2b, dial sense 4a

(2)

: an instrument for automatically making a diagram that indicates the pressure in and volume of the working fluid of an engine throughout the cycle

2

: any of a group of statistical values (such as level of employment) that taken together give an indication of the health of the economy

3

a

: a substance (such as litmus) used to show visually (as by change of color) the condition of a solution with respect to the presence of a particular material (such as a free acid or alkali)

b

: tracer sense 4b

4

: an organism or ecological community so strictly associated with particular environmental conditions that its presence is indicative of the existence of these conditions

indicatory

in-ˈdi-kə-ˌtȯr-ē 

adjective

Synonyms

• needle
• index
• gauge

Examples of indicator in a Sentence

Economic indicators suggest that prices will go up.

a control panel with various indicator lights

Recent Examples on the Web

Meanwhile, job growth hasn’t been as robust as other indicators have been, casting gloom over the housing market. —Preston Fore, Fortune, 27 Sep. 2025

Tailoring and construction are telltale indicators of quality, but not everyone can shell out for a custom couture ensemble. —Abbey Hudetz, Travel + Leisure, 27 Sep. 2025

Some waffle irons will indicate when the waffle is ready, but if your waffle iron doesn’t have an indicator, check for doneness when the steam subsides. —Robin Miller, AZCentral.com, 25 Sep. 2025

Emptying the dust cup was simple thanks to clear arrow indicators, although detaching it from the wand first added a small inconvenience. —Toni Sutton, PEOPLE, 25 Sep. 2025

Word History

First Known Use

1666, in the meaning defined at sense 1

Phrases Containing indicator

• plan position indicator

Rhymes for indicator

• activator
• actuator
• agitator
• alligator
• allocator
• alternator
• animator
• annotator
• applicator
• arbitrator
• aspirator
• aviator

Kids Definition

indicator

noun

in·​di·​ca·​tor ˈin-də-ˌkāt-ər 

1

: one that indicates: as

a

: a pointer on a dial or scale

b

: gauge entry 1 sense 2a

2

: a substance used to show visually (as by change of color) the presence of acid or base in a solution

Medical Definition

indicator

noun

in·​di·​ca·​tor ˈin-də-ˌkāt-ər 

: a substance (as a dye) used to show visually (as by a change in color) the condition of a solution with respect to the presence of a particular material (as a free acid or alkali)

litmus and phenolphthalein are acid-base indicators