tracer

[trey-ser]

noun

a person or thing that traces.

a person whose business or work is the tracing of missing property, parcels, persons, etc.

an inquiry sent from point to point to trace a missing shipment, parcel, or the like, as in a transportation system.

any of various devices for tracing drawings, plans, etc.

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.

the chemical substance contained in such ammunition.

a substance, especially a radioactive one, traced through a biological, chemical, or physical system in order to study the system.

Origin of tracer

First recorded in 1535–45; trace¹ + -er¹

Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

Examples from the Web for tracer

Contemporary Examples of tracer

Suddenly, the darkness came alive with muzzle flashes and tracer rounds.
From PTSD to Prison: Why Veterans Become Criminals
Matthew Wolfe
July 28, 2013
Tracer bullets, each with a descending arc, were zinging all around as Rigg swung LCI(L)-88 to the right.
The Story of the American Journalists Who Landed on D-Day
Timothy M. Gay
June 6, 2012
Below us, on Sultan Ismail Street, government troops thrust lances of tracer fire towards a horde of approaching cadavers.
The Extinction Parade: An Original Zombie Story by Max Brooks
Max Brooks
January 14, 2011

Historical Examples of tracer

It was a hellishly unbuildable and deceptively simple gadget, that tracer.
Zero Data
Charles Saphro
That there tracer started to hum again soon after you was out for a while.
Zero Data
Charles Saphro
He didn't know that there was a German in the sky, until he saw the tracer bullets.
High Adventure
James Norman Hall
Anything that goes out through it will have a tracer slapped onto it.
Skylark Three
Edward Elmer Smith
Then build me a tracer detector that'll pick it up at high velocity.
Skylark Three
Edward Elmer Smith

British Dictionary definitions for tracer

tracer

noun

a person or thing that traces

a projectile that can be observed when in flight by the burning of chemical substances in its base
ammunition consisting of such projectiles
(as modifier)tracer fire

med any radioactive isotope introduced into the body to study metabolic processes, absorption, etc, by following its progress through the body with a gamma camera or other detector

an investigation to trace missing cargo, mail, etc

Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Word Origin and History for tracer

c.1500, "one who tracks or searches," agent noun from verb form of trace (n.1). Meaning "bullet whose course is made visible" is from 1910.

tracer in Medicine

tracer

[trā′sər]

n.

A substance, such as a dye or a radioactive isotope, that is introduced into and followed through a biological or chemical process, by virtue of its radioactive signature, color, or other distinguishing physical property, thus providing information on the course of the process or on the components or events involved.

An instrument used in dissecting nerves and blood vessels.

tracer in Science

tracer

[trā′sər]

An identifiable substance, such as a dye or radioactive isotope, that can be followed through the course of a mechanical, chemical, or biological process. Tracers are used in radioimmunoassays and other laboratory testing. The use of radioactive iodine, for example, can give information about thyroid gland metabolism. Also called label