1. tracer(n = noun.person) - an investigator who is employed to find missing persons or missing goods;
2. tracer(n = noun.artifact) - an instrument used to make tracings;
Derived form verb trace2, verb trace7
3. tracer(n = noun.artifact) - (radiology) any radioactive isotope introduced into the body to study metabolism or other biological processes;
4. tracer(n = noun.artifact) tracer bullet - ammunition whose flight can be observed by a trail of smoke;
1. One who, or that which, traces. [1913 Webster]
2. A person engaged (esp. in the express or railway service) in tracing, or searching out, missing articles, as packages or freight cars. [Webster 1913 Suppl.]
3. An inquiry sent out (esp. in transportation service) for a missing article, as a letter or an express package. [Webster 1913 Suppl.]
4. a type of ammunition that emits light or smoke as it moves toward its target, providing a visible path of the projectile in flight so that the point of impact may be observed; -- called also
5. the chemical substance used in tracer ammunition to cause it to be visible in flight. [PJC]
6. a chemical substance with properties, such as radioactivity or fluorescence, which make it easily measurable, used to observe the movements of chemically related substances through a biological, physical, or chemical system; -- in biochemistry, also called
tracer, n.
1 a person or thing that traces.
2 Mil. a bullet etc. that is visible in flight because of flames etc. emitted.
3 an artificially produced radioactive isotope capable of being followed through the body by the radiation it produces.