Try Our Apps


Avoid these words. Seriously.


[foh-to-truh-piz-uh m, foh-toh-troh-piz-uh m] /foʊˈtɒ trəˌpɪz əm, ˌfoʊ toʊˈtroʊ pɪz əm/
noun, Botany.
phototropic tendency or growth.
Origin of phototropism
First recorded in 1895-1900; photo- + -tropism Unabridged
Based on the Random House Dictionary, © Random House, Inc. 2018.
Cite This Source
British Dictionary definitions for phototropism


the growth response of plant parts to the stimulus of light, producing a bending towards the light source
the response of animals to light; phototaxis
Derived Forms
phototropic, 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
Cite This Source
Word Origin and History for phototropism

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

Online Etymology Dictionary, © 2010 Douglas Harper
Cite This Source
phototropism in Medicine

phototropism pho·tot·ro·pism (fō-tŏt'rə-pĭz'əm)
Growth or movement of a sessile organism toward or away from a source of light.

pho'to·tro'pic (fō'tə-trō'pĭk, -trŏp'ĭk) adj.
The American Heritage® Stedman's Medical Dictionary
Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.
Cite This Source
phototropism in Science
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.
The American Heritage® Science Dictionary
Copyright © 2002. Published by Houghton Mifflin. All rights reserved.
Cite This Source

Word of the Day

Nearby words for phototropism

Difficulty index for phototropism

Few English speakers likely know this word

Word Value for phototropism

Scrabble Words With Friends