(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

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

plural of bite indicator

A float used by anglers to tell when a fish has taken the bait