Definition of auxin in US English:



  • A plant hormone which causes the elongation of cells in shoots and is involved in regulating plant growth.

    ‘the apex of a growing stem produces auxin’
    count noun ‘gibberellin interacts with cytokinins and auxins’
    • ‘Moreover, lateral root formation can be initiated by the application of the plant hormone auxin.’
    • ‘Falling levels of plant hormones such as auxin and the cytokinins are responsible.’
    • ‘Hormones such as auxins and gibberellins trigger fruit cells to expand.’
    • ‘The news release relates to auxin, a plant hormone known to function in plant growth and development.’
    • ‘New links to the plant hormone, auxin, were also uncovered.’


1930s: coined in German from Greek auxein ‘to increase’ + -in.