metamern.1
/ˈmɛtəmə/, U.S. /ˈmɛdəmər/ 1. Chemistry. A metameric compound; an isomer, spec. one differing in one or more functional groups. Cf. earlier metameride n. Now rare.
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the world > matter > chemistry > isomerism > [noun] > structural isomerism > functional group isomerism > metamer
metameride1857
metamer1865
1865 Proc. Royal Soc. 14 176 Fittig's isomeric hydrocarbons belong to the class of metamers having a different chemical structure.
1881 Nature 14 Apr. 566/1 Monoxy-benzene..an isomer or metamer of quinone.
1888 London, Edinb., & Dublin Philos. Mag. 5th Ser. 25 235 (note) The two methyl and ethyl metamers seem distinguishable.
1907 G. S. Newth Text-bk. Inorg. Chem. (ed. 12) 194 Different compounds having the same molecular weight and same percentage composition, but which do not belong to the same family of compounds, are distinguished as metamers.
1939 Industr. & Engin. Chem. (Industr. ed.) 31 944/2 This word [sc. elastomer] is reminiscent of isomer, electromer, metamer, and polymer.
1994 Org. Mass Spectrometry 29 347 The data obtained create the basis for distinguishing metamers.
2. Optics. A stimulus that is physically different from another stimulus but evokes the same perceptual response; esp. each of two or more colours with different spectral properties that are perceived by an observer as being indistinguishable.
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1931–3 J. S. Taylor tr. W. Ostwald Colour Sci. II. v. 38 Chromatic metamers.
1943 Science 18 June 545/2 If a red-green-blind observer be shown a pair of samples which match to the normal observer, he will be unable to discriminate them. That is, normal metamers are also metamers for the red-green blind.
1953 Sci. of Color (Optical Soc. Amer.) iv. 114/2 Many different spectral-energy distributions (called metamers) are capable of evoking identical color sensations in foveal vision.
1984 Jrnl. Optical Soc. Amer. A. 1 885 Practical colors are either suitably frequency limited to be represented by three samples or have suitably frequency-limited metamers.
2000 Nature Neurosci. 3 270 This approach explained a number of perceptual phenomena, including susceptibility of the motion system to direction metamers.
This entry has been updated (OED Third Edition, December 2001; most recently modified version published online March 2022).
metamern.2
/ˈmɛtəmə/, U.S. /ˈmɛdəmər/ 1. Zoology. = metamere n. 1. Now rare.
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the world > animals > animal body > general parts > [noun] > regions comprising segments > segment
articulation1765
segment1826
zoonite1838
somatome1856
somite1869
metamere1876
metamer1884
1884 Amer. Naturalist 18 271 Insects with..four metamers in the head.
1892 E. R. Lankester tr. E. Haeckel Hist. Creation (new ed.) II. xxiii. 233 Each segment or metamer possesses a part of the vascular system, of the muscular system, and of the nervous system, etc.
1939 Ann. Entomol. Soc. Amer. 32 695 Homotype: 1. That which is constructed on the same plan or type—as metamers. Not a nomenclatural term.
1988 Jrnl. Neurol., Neurosurg. & Psychiatry 51 197 The possibility of ejaculation after physostigmine mainly depended on the integrity of the T12-L2 metamers.
1997 Animal Biol. 6 47 Octopamine..added to the breeding water of Aeolosoma viride stimulated growth in terms of numbers of metamers.
2. Botany. A repeated unit of plant structure consisting of a leaf, node, internode, and axillary bud (if present). Also called phytomer. Cf. metamere n. 2.
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the world > plants > part of plant > cell or aggregate tissue > [noun] > tissue > phytomer or plant-unit
phyton1846
phytomer1879
metamere1887
metamer1900
1900 B. D. Jackson Gloss. Bot. Terms 157 Metamer, used by Sachs to denote a phyton or one of a number of similar parts of a series.
1935 Science 10 May 464/1 Infloresences, branches and metamers.
1979 Ann. Rev. Ecol. & Systematics 10 127 Particularly striking examples of vertical metamers are found in some desert shrubs.
1992 M. Ingrouille Diversity & Evol. Land Plants 38 Each metamer of the vegetative axis is the leaf, plus its place of attachment to the stem, called the node, and the portion of the stem between the node and the adjacent node called the internode.
This is a new entry (OED Third Edition, December 2001; most recently modified version published online March 2022).
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