[ dahy-mawr-fiz-uhm ]

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

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

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

Origin of dimorphism

First recorded in 1825–35; dimorph + -ism

Words Nearby dimorphism

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How to use dimorphism in a sentence

British Dictionary definitions for dimorphism


/ (daɪˈmɔːfɪzəm) /

  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

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

Derived forms of dimorphism

  • dimorphic or dimorphous, adjective

Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Scientific definitions for dimorphism


[ dī-môrfĭz′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.

  1. 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).

Other words from dimorphism

  • dimorphous adjective

The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.