Tracer
WordNet
noun
(1) Ammunition whose flight can be observed by a trail of smoke
(2) (radiology) any radioactive isotope introduced into the body to study metabolism or other biological processes
(3) An instrument used to make tracings
(4) An investigator who is employed to find missing persons or missing goods
WiktionaryText
Noun
- A chemical used to track the progress or history of a natural process.
- A piece of ammunition for a firearm that contains magnesium or another flammable substance arranged such that it will burn and produce a visible trail when fired at night.
- The act of tracking or investigating something.
- A person who traces something.