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 1d

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

Michael Wright, were flying near Kandahar Airfield, their Black Hawk came under machine-gun fire. Brightly lit tracer fire sliced across the sky, Wright said. Dan Lamothe, Anchorage Daily News, "How a McCain came home from war to mourn his famous father," 23 Aug. 2019 During a PET scan, a patient is injected with biologically active molecules known as tracers, which are tagged with radioactive atoms. Julie Grisham, Scientific American, "Faster, clearer PET images offer new views on disease," 9 July 2019 As the Khmer Rouge closed in, lighting up the night sky above Phnom Penh with explosions, flares and tracer bullets, he and his remaining staff were forced to evacuate on April 12, 1975, in a departure dubbed Operation Eagle Pull. Harrison Smith, Washington Post, "John Gunther Dean, ambassador haunted by U.S. departure from Cambodia, dies at 93," 11 June 2019 Cardenas saw a ditch, ran to it and began crawling along its banks, tracers whizzed over his head. Sig Christenson,, "At 100, ex-POW still hears the ‘Screaming Mimis’," 5 Aug. 2019 Sent on the job as additional muscle with Kimball was a manager of the Hobo Joe's on 16th Street and Camelback Road, who also worked part-time as a skip tracer., "Don Bolles files: Were the popular Hobo Joe's coffee shops connected to the Mafia?," 30 July 2019 The white ball soared into the gun-metal sky, like a tracer round towards the left side of the seventh fairway stretching out below. Rob Hodgetts, CNN, "Tiger Woods 'sore' and 'scraping it around' at the Open," 18 July 2019 The tracer technology will be used on five holes — 9, 10, 13, 15 and 18. Tod Leonard,, "Rory McIlroy aims to master intricacies of Augusta National in 10th tournament appearance," 4 Apr. 2018 As the Khmer Rouge closed in, lighting up the night sky above Phnom Penh with explosions, flares, and tracer bullets, he and his remaining staff were forced to evacuate on April 12, 1975. Harrison Smith,, "John Gunther Dean, ambassador haunted by US departure from Cambodia, dies at 93," 13 June 2019

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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Last Updated

17 Sep 2019

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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

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).


authorized for issue (as a bond)

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