tropism

1 of 2

noun

tro·​pism ˈtrō-ˌpi-zəm 

1

a

: involuntary orientation by an organism or one of its parts that involves turning or curving by movement or by differential growth and is a positive or negative response to a source of stimulation

b

: a reflex reaction involving a tropism

2

: an innate tendency to react in a definite manner to stimuli

broadly : a natural inclination : propensity

encouraged his tropism toward the theatrical

—John Updike

tropistic

trō-ˈpi-stik 

adjective

-tropism

2 of 2

noun combining form

: tropism

heliotropism

Did you know?

In hydrotropism, a plant's roots grow in the direction of increasing moisture, hoping to obtain water. In phototropism, a plant (or fungus) moves toward light, usually the sun—perhaps because, in the colder climates where such plants are usually found, concentrating the sun's warmth within the sun-seeking flower can create a warm and inviting environment for the insects that fertilize it. In thigmotropism, the organism moves in response to being touched; most climbing plants, for example, put out tiny tendrils that feel around for something solid and then attach themselves or curl around it. When microbiologists talk about tropism, however, they're often referring instead to the way a virus will seek out a particular type of cell to infect. And when intellectuals use the word, they usually mean a tendency shown by a person or group which they themselves might not even be aware of.

Examples of tropism in a Sentence

Recent Examples on the Web

Noun

The most important mutational changes affect the tissue tropism of the virus – its ability to infect a specific part of the body. —Emma Worden-Sapper, The Conversation, 16 Mar. 2023

Motive is tropism [seeking nutrients or energy] and virulence [ability to multiply and cause disease]. —Grant Delin, Discover Magazine, 11 May 2012

The music of Bizet and Gounod partakes of this tropism toward the elegant and pleasing. —Janet Malcolm, The New Yorker, 14 July 2022

Is this a late-life aberration, or can the tropism be traced to a deeper angst that was missed in its time? —The New Yorker, 18 Apr. 2022

In one way, the press conferences are a logical continuation of Trump’s tropism toward spectacle. —Megan Garber, The Atlantic, 24 Apr. 2020

Now, as with so much else, Trumpism is changing that tropism in unpredictable ways. —Bill McKibben, New Republic, 6 July 2017

Word History

Etymology

Noun

generalization of -tropism, after German Tropismus

Noun combining form

-trope or -trop(ic) + -ism, after German -tropismus

First Known Use

Noun

1893, in the meaning defined at sense 1a

Kids Definition

tropism

noun

tro·​pism ˈtrō-ˌpiz-əm 

: an automatic movement by an organism unable to move about from place to place and especially by a plant that involves a turning or growing toward or away from a stimulus (as light or moisture)

also : a reflex reaction involving such a movement compare taxis

tropistic

trō-ˈpis-tik 

adjective

Medical Definition

tropism

noun

tro·​pism ˈtrō-ˌpiz-əm 

: involuntary orientation by an organism or one of its parts that involves turning or curving by movement or by differential growth and is a positive or negative response to a source of stimulation

also : a reflex reaction involving a tropism

tropistic

trō-ˈpis-tik 

adjective