thermotropism

American  

[ther-mo-truh-piz-uhm] / θərˈmɒ trəˌpɪz əm /

noun

Biology.

1. oriented growth of an organism in response to heat.

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thermotropism British  

/ ˌθɜːməʊˈtrəʊpɪzəm /

noun

1. the directional growth of a plant in response to the stimulus of heat

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Other Word Forms

• thermotropic adjective

Etymology

Origin of thermotropism

First recorded in 1885–90; thermo- + -tropism

Explanation

When a plant's leaves curl in response to a chilly window, it's an example of thermotropism, which is an organism's tendency to move toward warmth and away from cold. In biology, a tropism is an involuntary response to a stimulus. Once you know that, you can probably easily guess that thermotropism is a tendency to respond to (and usually grow toward) heat, since thermo means "heat," from the Greek thermos. It's mostly a habit of plants, though it might also explain the popularity of saunas on very cold days.

Example Sentences

Moreover we know from experiments on heliotropism, thermotropism, etc., that even intangible stimuli such as rays of light, etc., impinging unsymmetrically on these delicate cells cause alterations in their behaviour—e.g. arrest or acceleration of growth.

From Disease in Plants by Ward, H. Marshall