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.

---

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

---

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

Office of Strategic Studies—the precursor to the Central Intelligence Agency—operating in the European theater.

From The Wall Street Journal ● Oct. 5, 2026

Named after a 18th century precursor to electric cells, LeydenJar uses a technique known as plasma deposition to make a lighter, more efficient anode – an essential component of all batteries.

From BBC ● Sep. 10, 2026

MeerKAT serves as a precursor telescope for that facility.

From Science Daily ● Sep. 9, 2026

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

The awesome supernova explosion ejects into space most of the matter of the precursor star—a little residual hydrogen and helium and significant amounts of other atoms, carbon and silicon, iron and uranium.

From "Cosmos" by Carl Sagan

They were the first known victims of the Shahed-136 drone, whose precursors had only appeared in Iranian state media and 2019 strikes on Saudi oil facilities.

From The Wall Street Journal ● Aug. 26, 2026

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

These sedimentary rocks contain petroleum precursors that have spent millions of years deep underground.

From Science Daily ● Jul. 9, 2026

Those wild cereal harvests were precursors to the domestication of the earliest crops, the cereals wheat and barley, in the Fertile Crescent.

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

Related Words

• forerunner
• harbinger