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[hee-lee-o-truh-piz-uh m, hee-lee-uh-troh-piz-uh m]
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  1. heliotropic tendency or growth.

Origin of heliotropism

First recorded in 1850–55; helio- + -tropism
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018

Examples from the Web for heliotropism

Historical Examples

  • The heliotropism of animals is identical with the heliotropism of plants.

    Darwin and Modern Science

    A.C. Seward and Others

  • We have mentioned the newly hatched larv of the barnacle in connection with heliotropism.

  • If it acts in a one-sided way, it causes the particular form of stimulation which we call phototaxis or heliotropism.

    The Wonders of Life

    Ernst Haeckel

  • We notice also the reverse phenomenon, namely, that chemical changes produced in the animal destroy its heliotropism.

    Darwin and Modern Science

    A.C. Seward and Others

  • These periodic motions are determined to a large extent, if not exclusively, by the heliotropism of these animals.

    Darwin and Modern Science

    A.C. Seward and Others

British Dictionary definitions for heliotropism


  1. the growth of plants or plant parts (esp flowers) in response to the stimulus of sunlight, so that they turn to face the sun
Derived Formsheliotropic (ˌhiːlɪəʊˈtrɒpɪk), adjectiveheliotropically, adverb
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 heliotropism


1854, from heliotrope + -ism.

Online Etymology Dictionary, © 2010 Douglas Harper

heliotropism in Science


  1. The growth or movement of a fixed organism, especially a plant, toward or away from sunlight. Heliotropism can be easily seen in sunflowers, which slowly turn their large flowers so that they continually face the sun.
Related formsheliotropic adjective (hēl′lē-ə-trōpĭk, -trŏpĭk)
The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.