a person whose business or work is the tracing of missing property, parcels, persons, etc.
3.
an inquiry sent from point to point to trace a missing shipment, parcel, or the like, as in a transportation system.
4.
any of various devices for tracing drawings, plans, etc.
5.
Also called tracer ammunition.ammunition containing a chemical substance that causes a projectile to trail smoke or fire so as to make its path visible and indicate a target to other firers, especially at night.