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 1a

(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 of indicator

• needle
• index

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

Research shows a higher diversity of microorganisms can be one indicator. —Will Stone, NPR, 22 June 2026

All areas are customizable, from a compass display to a large average gas mileage indicator. —James Raia, Mercury News, 21 June 2026

There were multiple offers and the property went under contract in about a month, a indicator that downtown apartment conversion projects in the last decade are attractive to investors who see occupancies remaining strong. —Kenneth R. Gosselin, Hartford Courant, 20 June 2026

The list considered 13 indicators and weights to measure global research performance and reputation, ranking the world's 2,250 top universities. —Mateo Rosiles, USA Today, 20 June 2026

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