perissadadj.n.

Brit.

/pᵻˈrɪsad/, U.S.

/pəˈrɪsæd/

Origin: A borrowing from Greek, combined with an English element. Etymons: Greek περισσός , -ad suffix¹.

Etymology: < ancient Greek περισσός superfluous, redundant, (in arithmetic) uneven, odd ( < πέριξ round about ( < περί (see peri- prefix) + a suffix of uncertain origin) + -ιος , suffix forming adjectives) + -ad suffix¹. Compare artiad adj. and n.This distinction of chemical valency appears to have originated with Odling (compare quot. 1864 at sense A. 1 and quot. 1922 at sense B.). With sense A. 2 compare earlier perissodactyl adj.

†A. adj.

1. Chemistry. Having a valency represented by an odd number. Obsolete.

ΚΠ

1864 W. Odling Tables Chem. Formulæ Table I (heading) Class I. Perissad elements and chlorides.

1871 Manufacturer & Builder Apr. 90/3 There is no use of..speaking of the artiad and perissad radicals before the student..has arrived at a practical common sense conception of what is understood by a radical.

1877 H. Watts Fownes's Man. Chem. I. 258 In every saturated or normal compound..the sum of the perissad elements is always an even number.

1881 Science 30 Apr. 202/2 There would have to be two forms at least one for artiad, and one for perissad atoms.

2. Zoology. = perissodactyl adj. Obsolete. rare.Apparently only attested in dictionaries or glossaries.

ΘΚΠ

the world > animals > mammals > group Ungulata (hoofed) > order Perissodactyla (odd-toed ungulates) > [adjective]

perissodactyl1848

perissodactylous1869

perissodactylic1888

perissodactylate1889

perissad1893

1893 New Sydenham Soc. Lexicon Perissad, belonging to the Perissodactyla.

B. n.

Chemistry. An element or radical whose valency is represented by an odd number. Contrasted with artiad adj. and n. Now disused.

ΘΚΠ

the world > matter > chemistry > valency > [noun] > element with odd-numbered valency

perissad1868

1868 J. D. Dana Syst. Mineral. (ed. 5) p. xvi In the combinations between elements of the former series occur..the ratios 1 : 1, 1 : 3, 1 : 5; and, with reference to the odd numbers 1, 3, 5, these elements are called perissads.

1870 H. Watts Dict. Chem. VI. 238 The elements may be divided in this respect into two classes, one of odd, the other of even equivalence, the former distinguished as perissads, the latter as artiads.

1922 Proc. Royal Soc. 1921–2 A. 100 p. vi The vapour density of calomel was found to correspond to the simple formula HgCl—a fact which contradicted the law of odds and evens (Odling's Perissads and Artiads).

This entry has been updated (OED Third Edition, December 2005; most recently modified version published online March 2022).

单词	perissad
释义	perissadadj.n. Brit. /pᵻˈrɪsad/, U.S. /pəˈrɪsæd/ Origin: A borrowing from Greek, combined with an English element. Etymons: Greek περισσός , -ad suffix¹. Etymology: < ancient Greek περισσός superfluous, redundant, (in arithmetic) uneven, odd ( < πέριξ round about ( < περί (see peri- prefix) + a suffix of uncertain origin) + -ιος , suffix forming adjectives) + -ad suffix¹. Compare artiad adj. and n.This distinction of chemical valency appears to have originated with Odling (compare quot. 1864 at sense A. 1 and quot. 1922 at sense B.). With sense A. 2 compare earlier perissodactyl adj. †A. adj. 1. Chemistry. Having a valency represented by an odd number. Obsolete. ΚΠ 1864 W. Odling Tables Chem. Formulæ Table I (heading) Class I. Perissad elements and chlorides. 1871 Manufacturer & Builder Apr. 90/3 There is no use of..speaking of the artiad and perissad radicals before the student..has arrived at a practical common sense conception of what is understood by a radical. 1877 H. Watts Fownes's Man. Chem. I. 258 In every saturated or normal compound..the sum of the perissad elements is always an even number. 1881 Science 30 Apr. 202/2 There would have to be two forms at least one for artiad, and one for perissad atoms. 2. Zoology. = perissodactyl adj. Obsolete. rare.Apparently only attested in dictionaries or glossaries. ΘΚΠ the world > animals > mammals > group Ungulata (hoofed) > order Perissodactyla (odd-toed ungulates) > [adjective] perissodactyl1848 perissodactylous1869 perissodactylic1888 perissodactylate1889 perissad1893 1893 New Sydenham Soc. Lexicon Perissad, belonging to the Perissodactyla. B. n. Chemistry. An element or radical whose valency is represented by an odd number. Contrasted with artiad adj. and n. Now disused. ΘΚΠ the world > matter > chemistry > valency > [noun] > element with odd-numbered valency perissad1868 1868 J. D. Dana Syst. Mineral. (ed. 5) p. xvi In the combinations between elements of the former series occur..the ratios 1 : 1, 1 : 3, 1 : 5; and, with reference to the odd numbers 1, 3, 5, these elements are called perissads. 1870 H. Watts Dict. Chem. VI. 238 The elements may be divided in this respect into two classes, one of odd, the other of even equivalence, the former distinguished as perissads, the latter as artiads. 1922 Proc. Royal Soc. 1921–2 A. 100 p. vi The vapour density of calomel was found to correspond to the simple formula HgCl—a fact which contradicted the law of odds and evens (Odling's Perissads and Artiads). This entry has been updated (OED Third Edition, December 2005; most recently modified version published online March 2022). < adj.n.1864
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