phototropism
noun
pho·tot·ro·pism
fō-ˈtä-trə-ˌpi-zəm 
: a tropism in which light is the orienting stimulus
Examples of phototropism in a Sentence
Recent Examples on the Web
Was phototropism wholly a molecular process, as some suspected, or could plants alter light beams to create a gradient and better direct their response?
—
Quanta Magazine, 31 Jan. 2024
That 50-50 split makes more sense than Gagliano’s result, says Mannie Liscum, a University of Missouri expert on plant phototropism — the way plants grow toward light.
—Anna Funk, Discover Magazine, 28 Aug. 2019
The reason for their odd behavior is likely something common to all plants: phototropism.
—Nathaniel Scharping, Discover Magazine, 6 June 2017
If the tree has grown at a slant all its life, it’s probably because of phototropism, Brosius says.
—Samantha Chery, Washington Post, 2 Aug. 2022
The leaning effect could be a result of phototropism, where plants naturally position themselves toward sunlight.
—Samantha Chery, Washington Post, 2 Aug. 2022
The fungus grows toward the hottest and most radioactive places, like phototropism but for deadly toxins.
—Caroline Delbert, Popular Mechanics, 6 Feb. 2020
The new polymer, described in a paper in the journal Nature Nanotechnology, is capable of phototropism, or the ability to follow the sun in its daily journey across the sky.
—Jason Daley, Smithsonian, 7 Nov. 2019
Examples are automatically compiled from online sources to
show current usage.
Read More
Opinions expressed in the examples do not represent those of Merriam-Webster or its editors.
Send us feedback.
Quanta Magazine, 31 Jan. 2024
That 50-50 split makes more sense than Gagliano’s result, says Mannie Liscum, a University of Missouri expert on plant phototropism — the way plants grow toward light.
—Anna Funk, Discover Magazine, 28 Aug. 2019
The reason for their odd behavior is likely something common to all plants: phototropism.
—Nathaniel Scharping, Discover Magazine, 6 June 2017
If the tree has grown at a slant all its life, it’s probably because of phototropism, Brosius says.
—Samantha Chery, Washington Post, 2 Aug. 2022
The leaning effect could be a result of phototropism, where plants naturally position themselves toward sunlight.
—Samantha Chery, Washington Post, 2 Aug. 2022
The fungus grows toward the hottest and most radioactive places, like phototropism but for deadly toxins.
—Caroline Delbert, Popular Mechanics, 6 Feb. 2020
The new polymer, described in a paper in the journal Nature Nanotechnology, is capable of phototropism, or the ability to follow the sun in its daily journey across the sky.
—Jason Daley, Smithsonian, 7 Nov. 2019
Cite this Entry
“Phototropism.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/phototropism. Accessed 8 Jul. 2025.
Copy CitationKids Definition
phototropism
noun
pho·tot·ro·pism
fō-ˈtä-trə-ˌpiz-əm
: a movement or growing in a particular direction that is made by a living thing in response to light
phototropic
adjective
ˌfōt-ə-ˈträp-ik
Medical Definition
phototropism
noun
pho·tot·ro·pism
fō-ˈtä-trə-ˌpiz-əm
ˌfōt-ō-ˈtrō-ˌpiz-əm
ˌfōt-ō-ˈtrō-ˌpiz-əm
1
: a tropism in which light is the orienting stimulus see heliotropism
2
: the reversible change in color of a substance produced by the formation of an isomeric modification when exposed to radiant energy (as light)
Love words? Need even more definitions?
Merriam-Webster unabridged
Share