dimorphism
(daɪˈmɔːfɪz(ə)m)
[mod. f. Gr. δίµορϕ-ος of two forms (see prec.) + -ism.]
The condition of being dimorphic. a. Cryst. The property of assuming two distinct crystalline forms, not derivable from each other.
| 1832 Johnston Progr. Chem. in Rep. Brit. Assoc. (1835) 432 The different causes to which, under different circumstances, dimorphism may be traced. 1850 Daubeny Atom. Th. iv. (ed. 2) 123 A familiar instance of dimorphism is exhibited in the case of carbonate of lime, which..is found, sometimes in the form of calcareous spar, sometimes in that of arragonite. 1851 Richardson Geol. v. 78 Dimorphism is a law which, though previously known, has been confirmed by the discoveries of Mitscherlich. |
b. Biol. The occurrence of two distinct forms of flowers, leaves, or other parts on the same plant or in the same species; or of two forms distinct in structure, size, colouring, etc. among animals of the same species.
| 1859 Darwin Orig. Spec. ii. (1878) 35 There are..cases of dimorphism and trimorphism, both with animals and plants. Thus..the females of certain..butterflies..regularly appear under two or even three conspicuously distinct forms. 1875 Bennett & Dyer tr. Sachs' Bot. iii. vi. 809 Another contrivance for..mutual fertilisation..Dimorphism (or Hetero⁓stylism)..In one individual the flowers all have a long style and short filaments, while in another individual all the flowers have a short style and long filaments. 1888 Rolleston & Jackson Anim. Life 238 The phrase sexual dimorphism is used to denote the differences other than the usual anatomical characters which separate the two sexes..In [Lepidoptera] the individuals of broods appearing at different times of the year often differ from one another..In this case the phrase seasonal dimorphism is employed. |
c. Philol. The existence, in one language, of a word under two different forms, or of two words of the same ultimate derivation (doublets).
| 1877 F. A. March Anglo-Sax. Gram. 28 Where it [bifurcation] is produced by a foreign word coming into English in different ways, it has been called dimorphism: ration, reason. |