dimorphism

American  

[dahy-mawr-fiz-uhm] / daɪˈmɔr fɪz əm /

noun

1. Zoology. the occurrence of two forms distinct in structure, coloration, etc., among animals of the same species.

2. Botany. the occurrence of two different forms of flowers, leaves, etc., on the same plant or on different plants of the same species.

3. Crystallography. the property of some substances of crystallizing in two chemically identical but crystallographically distinct forms.

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dimorphism British  

/ daɪˈmɔːfɪzəm /

noun

1. the occurrence within a plant of two distinct forms of any part, such as the leaves of some aquatic plants

2. the occurrence in an animal or plant species of two distinct types of individual

3. a property of certain substances that enables them to exist in two distinct crystalline forms

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dimorphism Scientific  

/ dī-môr′fĭz′əm /

1. The existence of two distinct types of individual within a species, usually differing in one or more characteristics such as coloration, size, and shape. The most familiar type of dimorphism is sexual dimorphism, as in many birds (where the male is often more brightly colored than the female), spiders (where the male is often smaller than the female), horned and tusked mammals (where horns and tusks are often present in the male but not the female), and in some species of deep-sea anglerfish (where the male is reduced to a tiny parasitic form attached for life to the much larger female). Fungi also display dimorphism. For example, the same species may exist as a small, budding yeast under some conditions, but as a mass of long hyphae under others.

2. The occurrence, among plants, of two different forms of the same basic structure, either on the same plant or among individuals of the same species. The common ivy Hedera helix produces juvenile leaves with prominent lobes under conditions of low light, but adult leaves of more rounded shape under conditions of greater light.

3. The characteristic of a chemical compound to crystallize in two different forms. Potassium feldspar, for example, can crystallize as either orthoclase (at higher temperatures) or microcline (at lower temperatures).

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Other Word Forms

• dimorphic
  adjective

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Etymology

Origin of dimorphism

First recorded in 1825–35; dimorph + -ism

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Example Sentences

See Examples For:

dimorphism

Scientists describe this type of physical difference between males and females as sexual dimorphism.

From Science Daily ● Sep. 4, 2026

"To me, the differences in sexual dimorphism among populations of beluga whales could indicate that mating systems also vary, and this is something we are currently working on," said O'Corry-Crowe.

From Science Daily ● Jun. 4, 2026

Brain cells and heart tissue cells likewise offer good examples of cell-level differences in addition to other levels at which sexual dimorphism makes male and female brains and hearts different, Ahmed noted.

From Salon ● Apr. 22, 2025

In species with pronounced size dimorphism, larger males compete with one another for access to females, and among the great apes larger males socially dominate females.

From Scientific American ● Oct. 17, 2023

Trimorphism and dimorphism in plants, papers on,  45.

From Charles Darwin: His Life in an Autobiographical Chapter, and in a Selected Series of His Published Letters by Charles Darwin

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