[pri-kur-ser, pree-kur-]


a person or thing that precedes, as in a job, a method, etc.; predecessor.
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.
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.
Biology. a cell or tissue that gives rise to a variant, specialized, or more mature form.

Origin of precursor

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

Synonyms for precursor Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

Examples from the Web for precursors

Contemporary Examples of precursors

  • It might actually be that there are no precursors; that nothing like this has happened before.

    The Daily Beast logo
    The Tripwire on Flight 370

    Clive Irving

    March 17, 2014

  • While a lot more information is needed before investigators can be sure of the cause, there are precursors that suggest a pattern.

    The Daily Beast logo
    Behind the Buffalo Crash

    Clive Irving

    February 13, 2009

Historical Examples of precursors

British Dictionary definitions for precursors



a person or thing that precedes and shows or announces someone or something to come; harbinger
a predecessor or forerunner
a chemical substance that gives rise to another more important substance

Word Origin for precursor

C16: from Latin praecursor one who runs in front, from praecurrere, from prae in front + currere to run
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Word Origin and History for precursors



early 15c., from Middle French precurseur and directly from Latin praecursor "forerunner," agent noun from past participle stem of praecurrere, from prae "before" (see pre-) + currere "to run" (see current (adj.)). Related: Precursory.

Online Etymology Dictionary, © 2010 Douglas Harper

precursors in Medicine


[prĭ-kûrsər, prēkûr′sər]


One that precedes and indicates something to come.
One that precedes another; a forerunner or predecessor.
A biochemical substance, such as an intermediate compound in a chain of enzymatic reactions, that gives rise to a more stable or definitive product.
The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.