01 n. One who, or that which, traces.
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1.
One who, or that which, traces.
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2.
A person engaged (esp. in the express or railway service) in tracing, or searching out, missing articles, as packages or freight cars.
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3.
An inquiry sent out (esp. in transportation service) for a missing article, as a letter or an express package.
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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 tracer ammunition.(Mil.) Also: tracer ammunition
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5.
the chemical substance used in tracer ammunition to cause it to be visible in flight.(Mil.)
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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 labeled compounds. Also: labeled compounds