precursor

American  

[pri-kur-ser, pree-kur-] / prɪˈkɜr sər, ˈpri kɜr- /

noun

• precursors
  plural

1. a person or thing that precedes, as in a job, a method, etc.; predecessor.

   Synonyms:

   forerunner

2. a person, animal, or thing that goes before and indicates the approach of someone or something else; harbinger.

   The first robin is a precursor of spring.

   Synonyms:

   herald

3. Chemistry, Biochemistry. a chemical that is transformed into another compound, as in the course of a chemical reaction, and therefore precedes that compound in the synthetic pathway.

   Cholesterol is a precursor of testosterone.

4. Biology. a cell or tissue that gives rise to a variant, specialized, or more mature form.

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precursor British  

/ prɪˈkɜːsə /

noun

1. a person or thing that precedes and shows or announces someone or something to come; harbinger

2. a predecessor or forerunner

3. a chemical substance that gives rise to another more important substance

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Other Word Forms

Noun Inflected Forms

• precursors
  plural

Etymology

Origin of precursor

1375–1425; late Middle English < Latin praecursor forerunner. See pre-, cursor

Explanation

You've heard the old saying "Pride comes before the fall?" Well, you could just as easily say pride is a precursor to the fall. A precursor is something that happens before something else. You don't have to be a dead languages scholar to guess that this word springs from a Latin source — praecursor, "to run before." A precursor is usually related to what it precedes. It's a catalyst or a harbinger, leading to what follows or providing a clue that it's going to happen. Binging on holiday candy is a precursor to tummy aches and promises to exercise more. Draconian policies in unstable nations are often a precursor to rebellion.

Example Sentences

See Examples For:

precursor precursors

Newton notes the Russell 3000 McClellan Summation Index — a breadth indicator — is sitting near its June peak and while, drifting sideways, hasn’t nosedived, which is often the precursor to a bigger downturn.

From MarketWatch ● Aug. 19, 2026

His subsequent research showed that these precursor cells multiply dramatically around the edges of brain wounds.

From Science Daily ● Aug. 14, 2026

She told BBC Radio 4's Today programme "the patterns were there, he was flying those red flags", and said there were "precursor offences" for which he could have stopped by police.

From BBC ● Aug. 8, 2026

He lived in a cramped, 12-person dorm room, working the assembly line at BBK Electronics, the precursor to smartphone giants Oppo and Vivo.

From The Wall Street Journal ● Aug. 7, 2026

In a way, that terrible episode became not only the precursor but also the symbol for all the horrible viciousness that would follow.

From "The Boy on the Wooden Box" by Leon Leyson

Directed by Henry Winkler and co-starring Lee Majors as Mountain Dan, it may be one of the earliest precursors to the Hallmark holiday-style movies.

From Salon ● Aug. 26, 2026

“The use of the books at issue to train Claude and its precursors was exceedingly transformative and was a fair use,” Alsup noted in his earlier judgment.

From Los Angeles Times ● Jul. 23, 2026

The White House document claimed they had discussed Chinese investment in U.S. industries, purchases of U.S. oil and agricultural products, and ending the flow of fentanyl precursors into the U.S.

From Slate ● May 16, 2026

The research, published in the journal Advanced Materials, introduces a scalable method for producing these nanoscrolls from MXene precursors while precisely controlling their shape and chemical composition.

From Science Daily ● Mar. 31, 2026

From the precursors of food production already practiced by hunter-gatherers, it developed stepwise.

From "Guns, Germs, and Steel: The Fates of Human Societies" by Jared M. Diamond

Related Words

• forerunner
• harbinger