pre·​cur·​sor | \ pri-ˈkər-sər , ˈprē-ˌkər- \

Definition of precursor

1a : one that precedes and indicates the approach of another
2 : a substance, cell, or cellular component from which another substance, cell, or cellular component is formed

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Other Words from precursor

precursory \ pri-​ˈkərs-​rē , -​ˈkər-​sə-​ \ adjective

Choose the Right Synonym for precursor

forerunner, precursor, harbinger, herald mean one that goes before or announces the coming of another. forerunner is applicable to anything that serves as a sign or presage. the blockade was the forerunner of war precursor applies to a person or thing paving the way for the success or accomplishment of another. 18th century poets like Burns were precursors of the Romantics harbinger and herald both apply, chiefly figuratively, to one that proclaims or announces the coming or arrival of a notable event. their early victory was the harbinger of a winning season the herald of a new age in medicine

Precursor Has Latin Roots

With its prefix pre-, meaning "before", a precursor is literally a "forerunner", and in fact forerunner first appeared as the translation of the Latin praecursor. But the two words function a little differently today. A forerunner may simply come before another thing, but a precursor generally paves the way for something. So, for example, the Office of Strategic Services in World War II was the immediate precursor of today's Central Intelligence Agency, while the blues music of the 1930s and 1940s was only one of the precursors of the rock and roll of today.

Examples of precursor in a Sentence

18th-century lyric poets like Robert Burns were precursors of the Romantics a precursor of the modern eggplant

Recent Examples on the Web

Edwardo Rodriguez, who was a deportation officer from 1996 to 2004 for the Immigration and Naturalization Service (Immigration and Customs Enforcement’s precursor), spoke at the panel. Silvia Foster-frau, San Antonio Express-News, "Organizations near and far take action against family separation," 1 June 2018 Marijuana, cocaine and heroin are among the hundreds of drugs and precursors on the list of substances travelers can declare. Dan Gartland,, "World Cup Fans Will Be Allowed to Have Marijuana, Cocaine, Heroin in Stadiums—With a Prescription," 1 Mar. 2018 Hundreds more are diagnosed with precursors that could lead to it. Leana Wen, SELF, "Before I Was President of Planned Parenthood, I Was Diagnosed With Cervical Cancer at a Routine Screening," 28 Jan. 2019 The pipeline also brings the cheap 4ANPP precursor from China to the U.S., then south of the border to Mexican cartel strongholds, where it is cut with other substances. Alex Riggins,, "Former San Diego-area Border Patrol agent admits to drug charge in federal court," 12 July 2018 Indeed, Huffington Post reporter Zach Carter specifically cites the Clinton and Obama administrations as precursors: 3. Jeet Heer, The New Republic, "The Trump administration takes a bold stance against mother’s milk.," 9 July 2018 In the new study, the researchers noted that herpes viruses were involved in networks that regulate these amyloid precursor proteins. Fiza Pirani, ajc, "Herpes virus may be linked to Alzheimer’s, study suggests," 22 June 2018 The viral genes seem to influence the expression, or activity, of genes associated with Alzheimer’s, including such famous ones as presenilin-1, BACE1, and several that direct the production of amyloid beta precursor proteins. Sharon Begley, STAT, "New study supports long-dismissed idea: Herpes viruses could play role in Alzheimer’s," 21 June 2018 The one now in force, adapted from a Dutch colonial precursor written in 1918, has not been revised since 1981. The Economist, "Why Indonesia is so bad at lawmaking," 21 June 2018

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'precursor.' 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 precursor

15th century, in the meaning defined at sense 1a

History and Etymology for precursor

Middle English precursoure, from Latin praecursor, from praecurrere to run before, from prae- pre- + currere to run — more at current

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Last Updated

17 Feb 2019

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Time Traveler for precursor

The first known use of precursor was in the 15th century

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English Language Learners Definition of precursor

somewhat formal : something that comes before something else and that often leads to or influences its development


pre·​cur·​sor | \ pri-ˈkər-sər , ˈprē-ˌ \

Medical Definition of precursor

1 : one that precedes and indicates the onset of another angina may be the precursor of a second infarction
2 : a substance, cell, or cellular component from which another substance, cell, or cellular component is formed especially by natural processes

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