pycno-
(pɪknəʊ)
bef. a vowel pycn-, combining form of Gr. πυκνό-ς ‘thick, dense’, forming various terms. (Occasionally spelt pykno-; erron. picno-.) ‖ pycnaˈspideæ Ornith. [Gr. ἀσπίς, ἀσπιδ- shield], in Sundevall's classification, a cohort of scutelliplantar passerine birds, having the planta or back of the tarsus studded with small irregular scales or plates; hence pycnaˈspidean a., belonging to the Pycnaspideæ; pycˈnaster [Gr. ἀστήρ star], a kind of sponge spicule; pycnoˈchlorite Min. [ad. G. pyknochlorit (J. Fromme 1903, in Min. und Petrogr. Mitt. XXII. 70)], a chlorite, (Mg,Fe2+,Al)6(Si,Al)4O10(OH)8, having the same silicon content as clinochlore (2·8–3·1 atoms per formula unit) but more iron (1·5–3 atoms); ˈpycnocline Physical Geogr., a thin layer separating water of different densities; pycnocoˈnidium Bot. [conidium] = pycnospore; ˈpycnodont Ichthyol. [Gr. ὀδούς, ὀδοντ- tooth], a. pertaining to or having the characteristics of the Pycnodontidæ, an extinct family of ganoid fishes typified by the genus Pycnodus, so called from the obtuse teeth on the palate and sides of the jaw; n. a pycnodont fish; so pycnoˈdontoid a. and n.; ˈpycnogon = pycnogonid; pycˈnogonid Zool. [f. mod.L. class name Pycnogonida, f. generic name Pycnogonum (M. T. Brünnich Entomologia (1764) 84), f. Gr. γόνυ knee], a marine arthropod of the group Pycnogonida, somewhat intermediate between Crustacea and Arachnida, typified by the parasitic genus Pycˈnogonum; a sea-spider; also attrib.; ‖ ˌpycnogoˈnidium Bot. [gonidium] = pycnospore; pycˈnogonoid Zool. [-oid] a., resembling or belonging to the Pycnogonida; n. a pycnogonid; ˌpycnohyˈdrometer: see quot.; pycˈnometer [-meter], a specific gravity flask; see gravity 4 d.; ‖ ˌpycnomeˈtochia (-ˈɒkɪə) Gram. [Gr. µετοχή participle], the close connexion or frequent use of participles or participial phrases; polymetochia; so ˌpycnomeˈtochic (-ˈɒkɪk) a., containing or using many participles; pycnoˈmetric a., involving or employing a pycnometer; hence pycnoˈmetrically adv.; pycnoˈmorphic a., Biol. [Gr. µορϕή shape, form], exhibiting dense formation or structure; † pycnoˈmorphous a. Cytology [ad. G. pyknomorph (F. Nissl in Neurol. Centralblatt (1894) XIII. 683, (1895) XIV. 70), f. Gr. µορϕή form, shape], characterized by much darkly staining matter; pycnoˈnotine a., Ornith. [Gr. νῶτος back], belonging to a sub-family of passerine birds, Pycnonotinæ, the bulbuls or rock-thrushes, typified by the genus Pycnonōtus; ˈpycnospore Bot. [Gr. σπόρος seed], = pycnidiospore; also = pycniospore s.v. pycnium.
| 1899 Evans Birds in Cambr. Nat. Hist. IX. 479 The metatarsus scutellated in front, and usually covered with small round scales behind (*pycnaspidean) is especially strong in Pyroderus and Rupicola. |
| 1888 Sollas in Challenger Rep. XXV. p. lxiv, *Pycnaster, a minute aster with short conical strongylate actines. This..might be regarded as a variety of the chiaster. |
| 1903 Mineral. Mag. XIII. 375 *Pyknochlorite... A greyish-green, compact chlorite occurring in a quartz and calcite vein in the gabbro of the Radauthal, Harz. It has the same general formula..as clinochlore, but differs from this in containing much more ferrous iron and in its compact (πυκνός) texture. 1960 Amer. Mineralogist XLV. 797 The co-existing chlorite occurs in fairly large pale green crystals and shows the typical anomalous interference colors. Its analysis shows it to be fairly rich in Mg and Al, and following the classification of Hey (1954) it may be termed a pycnochlorite, with Fe (total): (Fe + Mg) = 0·273 and Si 2·83, on the basis of 14 oxygens (anhydrous). 1973 Nature 2 Mar. 28/1 Microscopic studies reveal that the metamorphic boundary involves the replacement by quartz and a chlorite mineral of fixed composition (pycnochlorite). 1978 Ibid. 20 July 243/1 Chlorites occurring as matrix in greywacke and amygdule fillings and groundmass replacement in spilite are either pycnochlorite or diabantite. |
| 1957 G. E. Hutchinson Treat. Limnol. I. v. 282 When a wind blows over a thick layer of water lying over a second layer of greater density, not only will the surface level be raised at the lee end but the *pycnocline, or plane separating the two layers of different density, will be tilted in the opposite direction. 1967 Oceanogr. & Marine Biol. V. 278 Changes in the sinking rate..are well substantiated... In pycnoclines a retardation of passive organisms is frequent, sometimes associated with a synthesis of pigments. 1976 Nature 2 Sept. 8/1 Over large areas of the present-day ocean, a permanent density discontinuity (pycnocline) arises as a consequence of the latitudinal variation in the intensity of incident radiation from the Sun. |
| 1836 Buckland Geol. & Min. I. 281 The habits of the family of *Pycnodonts appear to have been omnivorous. 1862 Dana Man. Geol. 526 The Pycnodont group is now extinct. |
| 1927 Proc. Imper. Acad. Japan III. 610 (title) Notes on some *pycnogons living semi-parasitic on holothurians. 1935 T. H. Savory Arachnida xvi. 172 Ever since the first pycnogon was described..the problem of their affinities has been debated. 1959 A. C. Hardy Open Sea II. v. 100 Sea-slugs, ascidians, sea-spiders (pycnogons) and spider-crabs, starfish and brittlestars—all these, and more, may be in just one haul. |
| 1877 W. Thomson Voy. Challenger II. 349 The *Pycnogonida..attained an enormous size in cold Arctic and Antarctic water. 1881 Times 6 Jan. 4/6 We are promised very shortly similar volumes..on the Pycnogonids or nobody-crabs, on the seaweeds, and on certain groups of worms. 1935 T. H. Savory Arachnida xvi. 172 The Pycnogonid crawls about, extremely slowly. 1973 P. E. King Pycnogonids i. 7 The pycnogonid body is considerably reduced. Ibid. 8 The pycnogonids have a wide geographical and bathymetric range. |
| 1852 Dana Crust. ii. 1383 Of this last class are nearly all the Entomostraca, and with them the *Pycnogonoids. |
| 1884 Knight Dict. Mech. Suppl., *Picnohydrometer, a combination of the picnometer and hydrometer... Described in Scientific American, xxxiv. 340. |
| 1858 Thudichum Urine 33 The weight of the urine required to fill the *pycnometer is then ascertained. 1881 Nature XXIV. 294 The specific gravity bottle or pyknometer. |
| 1925 Arch. Internal Med. XXXV. 133 Specific gravity determinations were made by the *pyknometric method. 1938 Trans. Faraday Soc. XXXIV. 1214 (heading) Pyknometric studies on chemical equilibrium. |
| 1934 Jrnl. Chem. Soc. 498 The samples of water obtained by combustion were carefully distilled..and their densities were measured *pyknometrically. 1976 Nature 3 June 438/3 There is a reasonable agreement between X-ray and pycnometrically determined densities in the minerals of the oldest rocks. |
| 1900 Lancet 30 June 1849/2 The cell shows a distinct *pyknomorphic condition. |
| 1899 L. F. Barker New Syst. Constituent Neurones xi. 123 Nissl consequently designates the extremely darkly stained cells as *pyknomorphous cells, or cells in which the stainable portions are arranged relatively most closely. 1903 Med. Chron. XXXIX. 19 The stained, chromophile, or tigroid substance of nerve cells is regarded as nutritional substance. When it is abundant the cell is described as being in a pyknomorphous condition. |
| 1887 H. E. F. Garnsey tr. Ade Bary's Compar. Morphol. & Biol. Fungi v. 246 Pycnidia: receptacles..producing gonidia which are known as *pycnospores. 1898 tr. Strasburger's Text-bk. Bot. (1903) 352 Conidia..termed pycnospores or pycnoconidia. 1938 G. M. Smith Cryptogamic Bot. I. xii. 416 In addition to forming conidia or pycnospores, a mycelium may also form large thick-walled spores. |