Definitions
1.nounA compound, element, or isotope used to track the progress or history of a natural process.
2.nounA round 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 in the dark.
3.nounThe act or state of tracking or investigating something.
4.nounA request to trace the movements of a person or an object, such as a shipment.
5.nounA person who traces something.
6.nounA device or instrument used to assist in making tracings.