An indicator lamp (or indicator light) is an illuminated device that is intended to visually convey a single status to the user of a piece of equipment.
Indicator lamp may refer to:
Direction indicator light, a turn signal in automotive lighting Check engine light, a tell-tale warning light in automobiles Tell-tale (automotive), a more generic class of indicators A specific style of indicator light fixture or component, such as a: Neon glow lamp, a miniature gas-discharge lamp Digitron / cold cathode display / Nixie tube, an electronic device used for displaying numerals or other information using glow discharge Light-emitting diode
See also Search Wiktionary for indicator lamp or indicator light