Suddenly, the darkness came alive with muzzle flashes and tracer rounds.
Below us, on Sultan Ismail Street, government troops thrust lances of tracer fire towards a horde of approaching cadavers.
tracer bullets, each with a descending arc, were zinging all around as Rigg swung LCI(L)-88 to the right.
tracer trac·er (trā'sər)
A substance, such as a dye or a radioactive isotope, that is introduced into and followed through a biological or chemical process, by virtue of its radioactive signature, color, or other distinguishing physical property, thus providing information on the course of the process or on the components or events involved.
An instrument used in dissecting out nerves and blood vessels.
An identifiable substance, such as a dye or radioactive isotope, that can be followed through the course of a mechanical, chemical, or biological process. Tracers are used in radioimmunoassays and other laboratory testing. The use of radioactive iodine, for example, can give information about thyroid gland metabolism. Also called label.