TRACER

n. one who tracks down missing persons or property; substance used to make a bullet's path visible at night

Tracer may refer to:Histochemical tracer, a substance used for tracing purposes in histochemistry, the study of the composition of cells and tissuesIsotopic tracer, a substance with an isotope that has been enriched to a greater level than that found in natureRadioactive tracer, a substance containing a radioisotope that is used for tracking purposesFlow tracer, any fluid property used to track fluid motion: Dye tracerIn the ocean, salinity, potential temperature, and the concentration of many different chemical compoundsTracer ammunition, special bullets that burn brightly to enable the shooter to follow the bullets' trajectoriesMercury Tracer, an automobileTracer (DC Comics), a DC Comics characterTracer (Marvel Comics), a Marvel Comics supervillain
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Noun
1. an investigator who is employed to find missing persons or missing goods
(hypernym) detective, investigator, tec, police detective
2. an instrument used to make tracings
(hypernym) instrument
(derivation) trace
3. (radiology) any radioactive isotope introduced into the body to study metabolism or other biological processes
(hypernym) radioisotope
(classification) radiology
4. ammunition whose flight can be observed by a trail of smoke
(synonym) tracer bullet
(hypernym) ammunition, ammo

v. trace, mark; spoor, draw; write, delimit, delineate

(n.)
One who, or that which, traces.