red light

English Thesaurus

1. the signal to stop (noun.communication)

hypernym	:	stoplight, traffic light, traffic signal,
definition	:	a visual signal to control the flow of traffic at intersections (noun.communication)

2. a cautionary sign of danger (noun.communication)

hypernym	:	visual signal,
definition	:	a signal that involves visual communication (noun.communication)

hyponym	:	idiot light,
definition	:	a colored warning light on an instrument panel (as for low oil pressure) (noun.communication)