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 Overnight Monday and into Tuesday morning, Kabul’s sky filled with tracer fire, and the city shook with celebratory gunfire. Washington Post, 31 Aug. 2021 The militants would fire warning shots — sporadic rounds of automatic fire with the occasional orange streak of a tracer round. Alex Horton And Dan Lamothe, Anchorage Daily News, 28 Sep. 2021 Bluesign is an independent, third-party tracer of a textile’s route along the manufacturing process, making improvements at every stage from factory floor to finished product. Simon Mainwaring, Forbes, 8 Sep. 2021 Because the equation doesn’t test kidney function directly, its developers compared its results with kidney filtration rates measured using a more definitive test, based on a radioactive tracer, that is too complex to perform routinely. Jyoti Madhusoodanan, Science | AAAS, 22 July 2021 Hanson said Zink has influenced her work as a contact tracer. Marc Lester, Anchorage Daily News, 4 June 2021 Haney works as a contact tracer for Loudoun, telephoning people who, typically unwittingly, were recently near a person whose test results for the virus came back positive. Washington Post, 30 July 2021 Waters, of the Woodlawn neighborhood, lost her longtime job as a bartender during COVID-19 shutdowns, and is now working as a contact tracer and booking vaccine appointments at the nonprofit Ada S. McKinley Community Services. Karen Ann Cullotta,, 23 July 2021 Contact tracer Kandace Haney says people are mostly grateful to hear from her. Washington Post, 18 Sep. 2021

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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Time Traveler for tracer

Time Traveler

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

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Dictionary Entries Near tracer

trace of precipitation


tracer bullet

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Statistics for tracer

Last Updated

3 Jan 2022

Cite this Entry

“Tracer.” Dictionary, Merriam-Webster, Accessed 24 Jan. 2022.

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More Definitions for tracer



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
: 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

Thesaurus: All synonyms and antonyms for tracer

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


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