烽燧

烽燧	fēng suì	fire beacon tower (used in frontier regions in former times to relay information about the enemy, using smoke by day and fire at night)
烽	fēng	beacon fire
燧	suì	(bound form) material or tool used to light a fire by means of friction or the sun's rays / (bound form) beacon fire (alarm signal in border regions), esp. one lit during daytime to produce smoke