| 释义 |
migration|maɪˈgreɪʃən|
[ad. L. migrātiōn-em, n. of action f. migrāre to migrate.]
The action of moving from one place to another; also, an instance of this. a. gen. chiefly of things. spec. in Chem., the (non-random) movement from one place to another of an atom or group, e.g. within a molecule as part of a rearrangement of its structure, or towards an electrode during electrolysis.
1611Cotgr., Migration, a migration, a remouing, or shifting of places. 1650Hobbes De Corp. Pol. 133 The Tenets of Aristotle..concerning Substance and Accidents, Species, Hypostasis, and the Subsistence and Migration of Accidents from place to place. 1695Woodward Nat. Hist. Earth i. 45 Although such Alterations,..Transitions, and Migrations of the Centre of Gravity:..have actually happened, yet [etc.]. 1727–52Chambers Cycl. s.v., The migration of the souls of men into other animals after death. 1871Blackie Four Phases i. 154 To pray to the gods, that our migration hence may take place with good omens. 1873T. H. Green Introd. Pathol. (ed. 2) 100 The migration or transmission of elements from some primary growth, which..constitute the centres of secondary formations. 1875Jowett Plato (ed. 2) I. 373 There is a change and migration of the soul from this world to another. 1879Encycl. Brit. VIII. 108/2 For fused electrolytes a W-shaped tube..is sufficient; with solutions..the separation is more difficult, owing to the ‘migration of the ions’ and other causes. 1894tr. E. Goblet d'Alviella's Migration of Symbols 82 Is it not the Winged Circle, whose migrations I trace in another chapter? 1898Jrnl. Chem. Soc. LXXIII. i. 456 One of the following initial changes may occur. (1) Migration of the OH group. (2) Migration of the O·SO3H group as a whole. (3) Migration of a hydrogen atom of the ring, in the meta-position with regard to the side group. 1929Times 13 Nov. 11/1 A serious obstacle to the work of archæologists, historians and others..is the migration of manuscripts. 1938A. L. Raymond in H. Gilman Org. Chem. II. xvii. 148 The migration of the benzoyl group from position three to six in monoacetoneglucose. 1962D. H. Calam in A. Pirie Lens Metabolism Rel. Cataract 439 Although the differences in migration of a group of mono-amino, mono-carboxylic acids..are small, they are well separated by chromatography.
b. esp. of persons, a tribe: The action of moving from one country, locality, etc., to settle in another; also, simply, removal from one place of residence to another.
1646Sir T. Browne Pseud. Ep. vi. vi. 302 The first man ranged farre before the Flood, and laid his bones many miles from that place, where its presumed he received them: And this migration was the greater, if..he was cast out of the East-side of Paradise. 1766Blackstone Comm. II. 17 The right of migration, or sending colonies to find out new habitations. 1766Goldsm. Vic. W. i, All our adventures were by the fireside, and all our migrations from the blue bed to the brown. 1817Moore Lalla R. (1824) 290 A favourite resting place of the Emperors in their annual migrations to Cashmire. 1849Macaulay Hist. Eng. i. I. 10 In the ninth century, began the last great migration of the northern barbarians. 1891S. C. Scrivener Our Fields & Cities 49 The poverty of the majority is the cause of the continual migration to London.
c. Nat. Hist. Of animals: The action of moving in flocks, shoals, etc. from one region or habitat to another; spec. of some birds and fishes, the periodical departure from and return to a region at a particular season of the year. Also, of plants, change or extension of distribution. bathic migration (see quot. 1877). equatorial migration, ordinary meridional migration from or towards the equator.
1646Sir T. Browne Pseud. Ep. iv. xiii. 223 By this way Aristotle through all his bookes of Animals, distinguisheth their times of generation, Latitancy, migration, sanity and venation. 1704Ray Creation (ed. 4) 149 The migration of Birds..according to the Seasons. Ibid., The migration of divers sorts of Fishes. As for example; The Salmon. Ibid. 366 They [frogs travelling across dry land] had lived (till that time of their migration) in the Waters. 1830Lyell Princ. Geol. (1875) II. ii. xxxviii. 339 The former wide range of these quadrupeds implies a migration of Old World Forms into the new World. 1876A. R. Wallace Geog. Distrib. Anim. I. i. ii. 18 The term ‘migration’ is often applied to the periodical or irregular movements of all animals; but it may be questioned whether there are any regular migrants but birds and fishes. 1877G. B. Goode Menhaden 51 (U.S. Fish Comm. Rep.), The former may be called equatorial, the latter [i.e. changing to waters of less or greater depth] bathic migration. 1880Günther Fishes 648 Comparatively few are subject to periodical migrations to the sea, like Salmo. 1905F. E. Clements Res. Methods Ecol. iv. 216 Migration results when spores, seeds, fruits, offshoots, or plants are moved out of their home. 1932Fuller & Conard tr. Braun-Blanquet's Plant Sociol. xiii. 306 The first step in the development of vegetation is ‘migration’. 1966E. Palmer Plains of Camdeboo xvi. 270 White and Sloane wondering at the reasons for plant migrations. 1973Polunin & Smythies Flowers of S.-W. Europe ii. 86 The sierra..has acted as a refuge for a number of montane species, which had in all probability previously undergone migrations and recessions culminating in the last ice age.
d. Of a bodily organ: Alteration of position whether from normal or pathological causes.
1890in Syd. Soc. Lex.
¶ The alleged sense ‘Residence in a foreign country; banishment’ given in some recent Dicts. is fictitious. The word in the authority cited is a misreading of a later edition for ‘extermination’.
e. attrib. and Comb. (sense c), as migration-route; migration-station, a fixed place for the regular observation of the migration of birds.
1893Newton Dict. Birds 561 Every species on Migration goes its own way, and what is called a *Migration-route is only the coincidence of the way taken by more or fewer of them.
1884Science 17 Oct. 374/2 *Migration-stations now exist in every state and territory of the Union, excepting Delaware and Nevada. |