(chemistry) An acid-base indicator.

(aviation) An instrument that displays an aircraft's current airspeed.

(chemistry) any substance used to classify another, often by changing colour

A vote with no legal implication; a vote to test the prevalent mood in a given body of members

(economics) A form of economic planning based on imperfect information, employing grants, subsidies and other influences but not imposing mandatory quotas.

plural of airspeed indicator

plural of indicator function

(chemistry) A substance that exists in an oxidized and reduced forms, these forms having different colours, changing colour at a specific redox potential

plural of redox indicator

plural of attitude indicator