octa-
(ˈɒktə)
Gr. ὀκτα-, comb. form of ὀκτώ eight, with which it varies in some words. Most of the English derivatives of octa- appear in their places as main words; the following are of minor importance: octachronous (-ˈækrənəs) a. Pros. [Gr. χρόνος time] = octasemic. octacolic (-ˈkɒlɪk) a. Pros. [colon2], consisting of eight cola. octaphonic (-ˈfɒnɪk) a. Mus. [Gr. ϕωνή voice, sound], composed in eight parts. octapodic (-ˈpɒdɪk) a. Pros. [Gr. ὀκταπόδ-ης, ὀκτάπους, -ποδ- eight-footed], containing eight metrical feet; octapody (-ˈæpədɪ), a verse of eight feet. octasemic (-ˈsiːmɪk) a. Pros. [L. octasēmus, Gr. ὀκτάσηµος], containing eight moræ or units of time. octastrophic (-ˈstrɒfɪk) a. Pros., consisting of eight strophes or stanzas.
| 1900 H. W. Smyth Greek Metric Poets 195 We might arrange (the passage) in Octapodies. |
b. In
Chem. octa-,
oct- (sometimes
octo-) indicates the presence of eight atoms or units of an element or radical, as in
octacarbon,
octachloride,
octammonio-;
octadecanol, any of the alcohols with the formula C
18H
37OH;
spec. normal (or n-) octadecanol, a crystalline primary alcohol which is present in whale and dolphin oils, also called stearyl alcohol;
octaˈpeptide, any peptide composed of eight amino-acid residues.
| 1877 Octachloride [see octad 3]. |
| 1914 Jrnl. Chem. Soc. CV. 2233 The acetates of the dextrorotatory carbinols from ethylbutylcarbinol (γ-heptanol) on to ethylpentadecylcarbinol (γ-octadecanol) are all of negative rotation. 1949 E. Chain in H. W. Florey et al. Antibiotics II. xvii. 709 Antifoam reagent (3 per cent. octadecanol in lard oil). 1970 Chem. & Physics Lipids IV. 246 The major long-chain alcohols found in heart and brain tissues are hexadecanol, octadecanol and octadecenol. 1873 Watts Fownes' Chem. (ed. 11) 425 The octammonio⁓diplatinic compounds consist of double molecules of tetrammonio-platinic compounds having two or more molecules. |
| 1931 Chem. Rev. VIII. 390 Curtius..found that when his triglycylglycine ester was heated to 100°C. in vacuo it was converted into an insoluble infusible material having the composition—NHCH2CO—. He assigned to this material the structure of a cyclic octapeptide, but a much more highly polymeric open chain structure seems more probable. 1957 Science 3 May 886/1 (heading) Synthesis and pharmacology of the octapeptide angiotonin. 1972 Lancet 17 June 1320/1 The superb work of Wieland and his school established that the toxins are either cyclic heptapeptides or octapeptides. |