trac·​er | \ ˈtrā-sər How to pronounce tracer (audio) \

Definition of tracer

1 : one that traces, tracks down, or searches out: such as
a : a person who traces missing persons or property and especially goods lost in transit
b : 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 light
b : a substance used to trace the course of a chemical or biological process especially : label sense 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.

Recent Examples on the Web

Authorities have said the man, Douglas Haig, sold Paddock 720 rounds of tracer bullets. Fox News, "The Latest: Brother of Vegas shooter says he was delusional," 3 Aug. 2018 An officer hit by tracer shells, his wounds smoking, begs his men to shoot him. Daniel Todman, WSJ, "‘The Battle of Arnhem’ Review: The Dutch Dead End," 15 Oct. 2018 An able tracer of provenance, Walpole delighted in spoofing the past. Dominic Green, WSJ, "One Man’s Gothic Fantasy," 26 Oct. 2018 Typically, a chemical tracer would be added to the water, like a salt or dye, to track the flow. Kevin Davenport, idahostatesman, "Yellowstone's magma chamber is more powerful than we knew. Here's why studying it matters.," 3 July 2018 The radioactive tracer lights up on a computer monitor wherever the heart's blood vessels are blocked or bones are riddled with potentially cancerous tumors. Sarah Varney, Washington Post, "In Wisconsin, Hopes Rise For Production Of A Lifesaving Radioactive Isotope," 16 Jan. 2018 The wildfire was supposedly started by tracer rounds fired at a shooting range. Doyle Rice, USA TODAY, "Western wildfires: Thousands flee from dozens of blazes, including Colorado's 3rd-biggest on record," 5 July 2018 To trace how the cells and their progeny changed over time, the researchers equipped some of the single-cell fish embryos with genetic tracers: many tiny pieces of unique DNA, injected into the embryos' cytoplasm. Elizabeth Pennisi, Science | AAAS, "How one cell gives rise to an entire body," 26 Apr. 2018 Antiaircraft tracers lit up the skies over Damascus and explosive sounds bounced off the city’s hills, mixing with the mosques’ calls to prayer. Raja Abdulrahim, WSJ, "A Divided Syria Reacts Wearily to Airstrikes From the U.S. and Its Allies," 14 Apr. 2018

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'tracer.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

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First Known Use of tracer

14th century, in the meaning defined at sense 1

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The first known use of tracer was in the 14th century

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English Language Learners Definition of tracer

: 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


trac·​er | \ ˈtrā-sər How to pronounce tracer (audio) \

Medical Definition of tracer

: a substance used to trace the course of a process specifically : a labeled element or atom that can be traced throughout chemical or biological processes by its radioactivity or its unusual isotopic mass

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More from Merriam-Webster on tracer

Rhyming Dictionary: Words that rhyme with tracer

Nglish: Translation of tracer for Spanish Speakers Encyclopedia article about tracer

Comments on tracer

What made you want to look up tracer? Please tell us where you read or heard it (including the quote, if possible).


a sum of money that is sent as a payment

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