aux·​in | \ ˈȯk-sən How to pronounce auxin (audio) \

Definition of auxin

1 : any of various usually acidic organic substances that promote cell elongation in plant shoots and usually regulate other growth processes (such as root initiation): such as
b : any of various synthetic substances (such as 2,4-D) resembling indoleacetic acid in activity and used especially in research and agriculture

Other Words from auxin

auxinic \ ȯk-​ˈsi-​nik How to pronounce auxin (audio) \ adjective

Examples of auxin in a Sentence

Recent Examples on the Web By studying natural variations in root structure and the genetics associated with these variations, the team homed in on a previously unknown biological pathway that regulates auxin, a plant hormone that helps control root growth. San Diego Union-Tribune, 11 July 2019 Busch’s team identified a gene called EXOCYST70A3 that regulates auxin, without interfering with other pathways. San Diego Union-Tribune, 11 July 2019 The current consensus is that the movements of the growth hormone auxin and the proteins that transport it throughout a plant are responsible for such patterns. Maddie Burakoff, Smithsonian, 6 June 2019

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'auxin.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

First Known Use of auxin

1933, in the meaning defined at sense 1

History and Etymology for auxin

borrowed from German Auxin, from aux- (borrowed from Greek auxánein "to make grow, increase, strengthen," from aux- "grow" + -an-, verb formative marking completion) + -in -in entry 1 — more at eke entry 2

Note: The name Auxin was introduced by the German chemist Fritz Kögl (1897-1959) and his co-worker at the University of Utrecht, the Dutch chemist Arie Jan Haagen-Smit (1900-77), in the article "Über die Chemie des Wuchsstoffs (Communicated at the meeting of Dec. 19, 1931… by Prof. F.A.F.C. Went)," Koninklijke Akademie van Wetenschappen [Royal Netherlands Academy of Sciences], Proceedings of the Section of Sciences, vol. 34 (1931), pp. 1411-1416: "Wir schlagen für den Wuchsstoff die Bezeichnung Auxin (von auxánō [Greek letters] wachsen machen) vor, wobei es sich zur leichteren Namenbildung bei Derivaten empfehlen wird, hierunter die zugrundeliegende frei Säure zu verstehen" ("We suggest for the growth agent the designation auxin (from auxánō to cause to grow), to be recommended for the easier formation of derivative names, including the underlying free acid").

Learn More About auxin

Dictionary Entries Near auxin




See More Nearby Entries 

Statistics for auxin

Cite this Entry

“Auxin.” Dictionary, Merriam-Webster, Accessed 15 Aug. 2022.

Style: MLA
MLACheck Mark Icon ChicagoCheck Mark Icon APACheck Mark Icon Merriam-WebsterCheck Mark Icon

More Definitions for auxin


aux·​in | \ ˈȯk-sən How to pronounce auxin (audio) \

Medical Definition of auxin

: an organic substance that is able in low concentrations to promote elongation of plant shoots and usually to control other specific growth effects broadly : plant hormone

More from Merriam-Webster on auxin Encyclopedia article about auxin


Test Your Vocabulary

Challenging Words You Should Know

  • hedgehog reading a book
  • Often used to describe “the march of time,” what does inexorable mean?
Spell It

Can you spell these 10 commonly misspelled words?

Universal Daily Crossword

A daily challenge for crossword fanatics.

Love words? Need even more definitions?

Subscribe to America's largest dictionary and get thousands more definitions and advanced search—ad free!