(automotive) A turn signal or indicator. / (aviation) An instrument that shows both the current heading and the desired heading needed to follow a predetermined course.

plural of indicated airspeed

(aviation) The airspeed displayed by an aircraft's airspeed indicator based on measurements from the pitot-static system; the airspeed used by pilots and air traffic control when flying and controlling aircraft.

(Internet) A symbol conveying the tone or context of a message.

plural of tone indicator

Indian script with the structure of the Brahmic script, or one of its descendants.

plural of geographical indication

(chemistry) A substance that shows the acidity or alkalinity of a solution by its colour.

(aviation) An aircraft instrument that provides an indication of the vertical change in position.

(aviation) An instrument installed in an aircraft that indicates the rate at which the aircraft is gaining or losing altitude.