a device for showing the operating condition of some system
a signal for attracting attention
(chemistry) a substance that changes color to indicate the presence of some ion or substance; can be used to indicate the completion of a chemical reaction or (in medicine) to test for a particular reaction
in or to a backstage area of a theater; "costumes were changed backstage"
out of view of the public; behind the scenes; "Working backstage to gain political support for his proposal"; "many private deals were made backstage at the convention"
conceal one's true motives from especially by elaborately feigning good intentions so as to gain an end; "He bamboozled his professors into thinking that he knew the subject well"