Definition of tracer
1 : one that traces, tracks down, or searches out: such asa : a person who traces missing persons or property and especially goods lost in transitb : an inquiry sent out in tracing a shipment lost in transit
2 : one who traces designs, patterns, or markings
3 : a device (such as a stylus) used in tracing
4a : ammunition containing a chemical composition to mark the flight of projectiles by a trail of smoke or lightb : a substance used to trace the course of a chemical or biological process; especially : label 3d
Examples of tracer in a sentence
The enemy fired tracers at the aircraft carrier.
They injected her with a radioactive tracer and tracked it via X-rays.
First Known Use of tracer
TRACER Defined for English Language Learners
Definition of tracer for English Language Learners
: a type of bullet that shows its path by creating smoke or light as it moves through the air
medical : a substance that is put in a patient's body so that doctors can watch a biological process (such as digestion) or see how a condition (such as cancer) is progressing
Seen and Heard
What made you want to look up tracer? Please tell us where you read or heard it (including the quote, if possible).