tracer

[ trey-ser ]

/ ˈtreɪ sər /

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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.

QUIZ

THINGAMABOB OR THINGUMMY: CAN YOU DISTINGUISH BETWEEN THE US AND UK TERMS IN THIS QUIZ?

Do you know the difference between everyday US and UK terminology? Test yourself with this quiz on words that differ across the Atlantic.

Question 1 of 7

In the UK, COTTON CANDY is more commonly known as…

candystring

candyfloss

candypuff

TAKE THE QUIZ TO FIND OUT

Origin of tracer

First recorded in 1535–45; trace¹ + -er¹

Words nearby tracer

trace, traceable, trace element, trace fossil, traceless, tracer, tracer bullet, traceried, tracery, traces, traceur

Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2023

How to use tracer in a sentence

Contact tracers tried to identify everyone exposed and figure out where the virus might have come from.
Smallpox used to kill millions of people every year. Here’s how humans beat it.|Kelsey Piper|February 5, 2021|Vox
If somebody tests positive for covid-19, contact tracers use it to track down those who got close enough to be potentially infected.
Broken promises: How Singapore lost trust on contact tracing privacy|Bobbie Johnson|January 11, 2021|MIT Technology Review
America’s pandemic response has suffered from a well-publicized lack of PPE, of tests, of contact tracers.
A depleted workforce and no end in sight: An inside look at America’s ailing health care industry|Erika Fry|December 8, 2020|Fortune
Spotting the novel virus as early as possible can signal infectious people to isolate themselves, and help contact tracers identify and notify anyone they’ve been in close quarters with.
The 100 greatest innovations of 2020|Popular Science Staff|December 2, 2020|Popular-Science

Contact tracers in Anne Arundel County reached out to families every day to check on possible symptoms.
After telling more than 800 athletes and coaches to quarantine, a county halts youth sports|Ovetta Wiggins|November 30, 2020|Washington Post
Suddenly, the darkness came alive with muzzle flashes and tracer rounds.
From PTSD to Prison: Why Veterans Become Criminals|Matthew Wolfe|July 28, 2013|DAILY BEAST
First, however, I was injected with a radioactive tracer that allowed activity in my brain to show up on the scan.
Can Daniel Amen Read Your Mind?|Eliza Shapiro|December 14, 2012|DAILY BEAST
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|DAILY BEAST
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|DAILY BEAST
Three men snapped down behind the tracer-guns, firing without aiming, in a frenzied attempt to catch the fleeing sled.
Derelict|Alan Edward Nourse
Firing was incessant from the beginning, and the air seemed blue with tracer smoke.
The Heroic Record of the British Navy|Archibald Hurd
Here I am, a mechanical engineer, about to tackle the job of a professional detective and tracer of missing persons.
Highways in Hiding|George Oliver Smith
A thin stream of glowing red and orange tracer bullets soared up at the plane from the Catanzas side of the bay.
The Five Arrows|Allan Chase
Every tenth bullet was a tracer that made a white trail in the sky allowing you to track them.
The Biography of a Rabbit|Roy Benson

British Dictionary definitions for tracer

tracer

/ (ˈtreɪsə) /

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

Scientific definitions for tracer

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