1
2
: one who traces designs, patterns, or markings
3
: a device (such as a stylus) used in tracing
4
a
: 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
Another video from a separate location along Al Rashid Street, released by Al Jazeera, also shows horizontal tracer rounds, likely originating from the southwest, traveling left to right as a huge crowd gathers around the trucks.
—
Katie Polglase, CNN, 9 Apr. 2024
Red streaks of tracer ammunition, used to help soldiers aim, are seen several times above the crowd.
—Leila Sackur, NBC News, 14 Mar. 2024
See all Example Sentences for tracer 
Katie Polglase, CNN, 9 Apr. 2024
Red streaks of tracer ammunition, used to help soldiers aim, are seen several times above the crowd.
—Leila Sackur, NBC News, 14 Mar. 2024
See all Example Sentences for tracer
These examples are programmatically compiled from various online sources to illustrate current usage of the word 'tracer.' Any opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback about these examples.
Dictionary Entries Near tracer
Cite this Entry
“Tracer.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/tracer. Accessed 31 May. 2024.
Copy CitationKids Definition
tracer
noun
trac·er
ˈtrā-sər 
1
a
: a person who traces missing persons or property
b
: an inquiry sent out in tracing a shipment lost in transit
2
a
: ammunition containing a chemical composition to mark the flight of projectiles by a trail of smoke or fire
b
: a substance and especially a labeled element or atom used to trace the course of a chemical or biological process
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