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A.Word.A.Day--tropism

"Not that I want to be a god or a hero. Just to change into a tree, grow for ages, not hurt anyone." Using trees as the metaphor, these poignant words of Nobel prizewinner Czeslaw Milosz sum up what it truly means to be human. Perhaps we in the animal kingdom can learn much from those in the plant kingdom.

This week we feature words related to plants, and as today's example shows, we don't have to keep these terms only for our leafy friends. One can use many of these words in other contexts, alluding to human behavior.

tropism (TRO-piz-uhm) noun

The turning or bending (typically by growth instead of movement) of an organism in response to an external stimulus.

[From Greek tropos (turning). Ultimately from Indo-European root trep- (to turn) that also gave us troubadour, tropic, entropy, and contrive.]

See more usage examples of tropism in Vocabulary.com's dictionary.

If you've ever noticed a plant bending towards the light, you've seen an example of tropism. The term is usually applied to plants. The response to a stimulus could be positive or negative: towards or away from the stimulus. Some examples of stimuli are light (phototropism), gravity (geotropism), heat (thermotropism), touch (thigmotropism), and water (hydrotropism).

Darwin and his son Francis demonstrated that the tip of the plant detected light and if you covered just the tip, the plant would grow straight, not toward the light.

The word tropism is related to trope, the term for rhetorical devices such as metaphor and irony. The idea is that the words in those rhetorical devices are turned in a special way.

"The traits [Judith Miller] has drive many reporters at The Times crazy: her tropism toward powerful men, her frantic intensity, and her peculiar mixture of hard work and hauteur."
Maureen Dowd; Woman of Mass Destruction; The New York Times; Oct 22, 2005.

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