1. (n.) A picture taken by heliography; a photograph.

2. (n.) An instrument for taking photographs of the sun.

3. (n.) An apparatus for telegraphing by means of the sun's rays. See Heliotrope.

Angelus Angelus bell Roman candle abject fear admonishment admonition affright aid to navigation alarum alert amaze amber light anxiety apprehension arouse astonish awe balefire battle cry beacon beacon fire bell bell buoy birdcall blinker blue funk blue peter bugle call buoy call caution caution light caveat cold feet consternation cowardice cry havoc cry wolf curdle the blood daunt deterrent example discomfort dismay disquiet distress disturb dread example excitement fear final notice final warning flare fly storm warnings fog bell fog signal fog whistle foghorn forewarning fright frighten funk glance go light gong gong buoy green light heliograph high sign hint horn horrification horripilate horror international alphabet flag international numeral pennant kick last post leer lesson make one tremble marker beacon monition moose call moral nervousness nod notice notification nudge object lesson panic panic fear parachute flare phobia pilot flag poke police whistle prenotice quarantine flag radio beacon raise apprehensions rallying cry rebel yell red flag red light reveille rocket sailing aid scare semaphore semaphore flag semaphore telegraph shake sign signal signal beacon signal bell signal fire signal flag signal gong signal gun signal lamp signal light signal mast signal post signal rocket signal shot signal siren signal tower siren sound the alarm sound the tocsin spar buoy spook stagger stampede startle stop light strain stress summons surprise taps tension terrify terror terrorize the nod the wink threat tip-off tocsin touch traffic light traffic signal trepidation trumpet call ultimatum uneasiness unholy dread unman unnerve unstring upset verbum sapienti war cry warn warning warning piece watch fire whistle white flag wigwag wigwag flag wink yellow flag