• synonyms


[foh-to-truh-piz-uh m, foh-toh-troh-piz-uh m]
noun Botany.
  1. phototropic tendency or growth.
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Origin of phototropism

First recorded in 1895–1900; photo- + -tropism
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018

British Dictionary definitions for phototropism


  1. the growth response of plant parts to the stimulus of light, producing a bending towards the light source
  2. the response of animals to light; phototaxis
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Derived Formsphototropic, adjective
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 phototropism


1899, from German phototropie (1892), from photo- + tropism.

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Online Etymology Dictionary, © 2010 Douglas Harper

phototropism in Medicine


  1. Growth or movement of a sessile organism toward or away from a source of light.
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Related formspho′to•tropic (fō′tə-trōpĭk, -trŏpĭk) adj.
The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.

phototropism in Science


  1. The growth or movement of a fixed organism toward or away from light. In plants, phototropism is a response to blue wavelengths of light and is caused by a redistribution of auxin from the illuminated side to the darker side of the shoot, resulting in quicker growth on the darker side and bending of the shoot toward the source of light. Certain sessile invertebrates also exhibit phototropism.
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The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.