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noun

tracer

TRAY-suh

Tracer (noun) means a substance, such as a radioactive isotope or dye, used to track how something moves or changes through a system. Example: “Doctors injected a radioactive tracer to follow blood flow through the heart.”

noun
1
A substance, such as a radioactive isotope or dye, used to track how something moves or changes through a system.
"Doctors injected a radioactive tracer to follow blood flow through the heart."
2
A bullet or shell that leaves a visible trail of light so its path can be seen, especially at night.
"Tracer rounds lit up the night sky during the battle."

How to use tracer

Learner’s notes

In plain EnglishSomething used to track a path — either a marked substance followed through a body or system, or a glowing round of ammunition.

Common pairings
radioactive tracer tracer bullet tracer round

Word forms

tracers plural

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Fill the gap

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Doctors injected a radioactive _____ to follow blood flow through the heart.

Etymology

From trace + -er.

tracer bullet

Rhymes for tracer

See all rhymes for tracer →

Frequently asked questions

What does “tracer” mean?

The word “tracer” means a substance, such as a radioactive isotope or dye, used to track how something moves or changes through a system. In plain terms, something used to track a path — either a marked substance followed through a body or system, or a glowing round of ammunition.

How do you pronounce “tracer”?

“Tracer” is pronounced TRAY-suh (/ˈtɹeɪsɚ/ in IPA).

How do you use “tracer” in a sentence?

Here is “tracer” used in a sentence: “Doctors injected a radioactive tracer to follow blood flow through the heart.”

What part of speech is “tracer”?

“Tracer” is a noun.

How many meanings does “tracer” have?

“Tracer” has 2 distinct senses listed in this dictionary. The most common is: a substance, such as a radioactive isotope or dye, used to track how something moves or changes through a system.

Definitions: FreeDict original editorial · etymology from Wiktionary