| 释义 |
▪ I. overlap, n.|ˈəʊvəlæp|
[f. overlap v.]
1. a. An occurrence or instance of overlapping; a partial superposition or coincidence; the part or place at which one edge or thing overlaps another; spec. in Geol. (see next, 3). Also transf. and fig.
1813S. Smith Agric. Surv. Galloway 85 (Jam.) When the stones are small, the dykes should be proportionally narrowed, to make the two sides connect more firmly, and afford more overlaps. 1852Jrnl. R. Agric. Soc. XIII. ii. 298 The nails..are driven through the overlap of both sheets at a time. 1880Dawkins Early Man i. 4 What we may term the overlap of history [on archæology]. 1931A. Keith Place of Prejudice 19 Head and heart are never quite separated; there is a large overlap in their fields of action. 1955Bull. Atomic Sci. June 205/3 Perhaps outside help with parts of the investigation should be arranged, with some of the ‘second laboratory’ type of overlap providing the spur of competition. 1960Times 31 Oct. 4/4 Later Glover scored a good try after Willcox had made the overlap in a set-piece movement. 1962L. Deighton Ipcress File xxiv. 156 That camera went out of action..but luckily we have overlap on the camera fields. 1970K. Ball Fiat 600, 600D Autobook 164/2 Overlap, period during which inlet and exhaust valves are open together. 1970Times 1 Oct. 10/3 Hollins again at the 29th minute..joined in an overlap with Mulligan. 1974Country Life 3/10 Jan. 25/3 For the Garvan Gallery the William and Mary style runs from 1685 to 1730, Queen Anne from 1715 to 1765, Chippendale from 1750 to 1790 and Federal from 1788 to 1830. The overlaps are perfectly acceptable. 1974Times 19 Dec. 6/8 There is a considerable overlap between the committee's membership and that of the Council for..Arab-British understanding. 1975Times 11 Jan. 12/4 Allowing for duplications and overlaps..the CIA..‘spies on 100,000,000 Americans’. 1976Sunday Post (Glasgow) 26 Dec. 36/2 Better goal-kicking did the trick, since the try count was three-all, but Gala could have popped the result into their Christmas stockings a lot earlier if they had not so persistently kicked away overlaps.
b. In yacht-racing, a position in which a yacht overtaking another is debarred by the rules from passing one side, or in which the yachts concerned cannot turn toward each other without risking a collision.
1898Encycl. Sport II. 585/2 If in rounding any mark in a race, or any obstruction, an inside yacht has an overlap, the outside yacht or yachts must give her sufficient room. 1935Encycl. Sports 760/2 Provided that the overtaking yacht makes her overlap on the side opposite to that on which the overtaken yacht then carries her main boom, the latter may luff as she pleases [etc.]. 1958Times 23 Sept. 14/2 The American yacht then went smoothly forwards to establish an overlap.
c. Phonetics. Concurrence of the concluding sound of one phoneme with the opening of the next, as represented spectrographically; homonymy (as French /sã/, cent and sans).
1942Amer. Speech XVII. 42 There is no over-lap between the length of this vowel when full grade..and its length when reduced grade. 1964Language XL. 62 It is possible to raise the question of phonemic overlap... This instance of overlapping phonetic values..need not be regarded as a violation of phonemic principles.
d. Linguistics. (See quot. 1948).
1948E. A. Nida in Language XXIV. 431 Instances of ‘overlap’, i.e. forms which are in complementary distribution except at certain points where there is a contrast resulting from fluctuation of forms. 1973Archivum Linguisticum IV. 12 /de/ and /bi/ and /bi/ and /na/ do have areas of overlap.
2. Geol. The extension of a stratum beyond or over the edges of younger underlying strata; also, the upper stratum; esp. = onlap (a transgressive overlap); also = offlap (a regressive overlap); less commonly = overstep n. 2.
1846H. T. De la Beche in Mem. Geol. Survey Gt. Brit. I. 24 Proceeding westward..the overlap of the Old Red Sandstone becomes such that from Middleton Hall to the vicinity of Caermarthen, it rests on the lower Silurian rocks, covering up the higher Silurian beds. 1846A. C. Ramsay in Ibid. 319 This..shows a tendency to a certain amount of contemporary depression of coast and sea bottom on the south to admit of an overlap during the formation of these deposits. 1857Jukes Stud. Man. Geol. vii. 262 Overlap may take place in a perfectly continuous series, merely proving the fact of a depression of the area contemporaneously with that deposition. 1876Q. Jrnl. Geol. Soc. XXXII. 377 By the term overlap no unconformity is here meant, but the concealment of lower beds by the extension, through a progressive subsidence, of those next in time upon the old rocks. 1883[see overstep n. 2]. 1906A. W. Grabau in Bull. Geol. Soc. Amer. XVII. 569 The types of overlap of sedimentary strata may be classified as follows: A. Irregular or discontinuous overlap. B. Regular continuous or progressive overlap. 1. Marine. a. Transgressive. b. Regressive. 2. Non-marine. c. Fluviatile. 1913, etc. [see offlap]. 1947Bull. Amer. Assoc. Petroleum Geol. XXXI. 1868 There is much confusion in the uses of the word ‘overlap’ in geological literature. In recent years it has often been used to describe..: (1) the regular and progressive pinching-out of sediments above unconformities, and (2) the regular truncation of sediments below unconformities. 1962Read & Watson Introd. Geol. xii. 616 Stratigraphical traps are the result of unconformities, lensing, overlap and reflected buried hills. 1972B. B. Brock Global Approach to Geol. xvii. 224 The Lower Division forms remnants of a regressive overlap left by a contracting and retreating inland basin.
3. Railways. The distance beyond a signal that must be unoccupied before an engine is allowed to approach it past the previous signal.
1925Tweedie & Lascelles Mod. Railway Signalling x. 145 To work without overlaps it would be necessary to have some system of positive speed control which would bring a train to a stand at a stop signal independently of the driver. 1956Railway Mag. Mar. 351/2 The standard British block telegraph overlap of 440 yd. beyond the home..signal can be modified by special instructions. 1969H. R. Broadbent Introd. Railway Braking i. 6 The overlap beyond the stop signal is therefore a form of margin on the distance between the warning and stop signals to cover for contingencies.
4. Computers. The strictly simultaneous performance of two or more operations during the execution of a program.
1963L. Schultz Digital Processing xi. 239 In a machine with a modular memory..the execution of a program might be significantly speeded by locating variables in one module and instructions in another, and by providing an overlap in the time needed for executing one instruction and fetching the next. 1969P. B. Jordain Condensed Computer Encycl. 365 I/O overlap is a great improvement over strictly sequential operations, but it still leaves the electronics waiting for the slower main memory.
5. attrib. overlap fault, an overthrust fault; overlap joint, a joint in which one edge overlaps the other, instead of merely butting against it.
1883W. S. Gresley Gloss. Terms Coal Mining 180 Overlap fault, a peculiar kind of fault where a seam is reversed or doubled back over itself. 1886J. Prestwich Geol. I. xv. 257 (caption) Great slide or overlap fault in the Radstock coalfield.
▪ II. overlap, v.|əʊvəˈlæp|
Also 8 -lop.
[f. over- 8 + lap v.2 (cf. esp. sense 7, lap over). In sense 4 partly at least from lap v.1]
1. a. trans. To lap over; to lie or be situated so as partly to extend over and cover part of (something else); to overlie partially. Also fig. To extend over part of the (non-physical) territory, period, etc., occupied by (another thing); to coincide partly with.
1726A. Munro Anat. Bones ii. 74 An Infant, one of whose Ossa parietalia overloped the other. Ibid. (1782) 82 These cells..are overlopped by the maxillary bones. 1813S. Smith Agric. Surv. Galloway 88 (Jam.) It is essential..that the stones frequently overlap one another. 1872Nicholson Palæont. 323 Ganoids in which the scales are rounded and overlap one another. 1887Saintsbury Hist. Elizab. Lit. v. (1890) 159 Their lives overlapped each other considerably. a1904Mod. The lead overlaps the uppermost row of slates.
b. absol. or intr., usually in reciprocal sense.
1799Kirwan Geol. Ess. 285 In the Pyrenees, they sometimes overlap. 1886Stubbs Lect. Med. & Mod. Hist. xiii. 296 Three conjoint systems of jurisprudence..overlapping. 1911R. Brooke Let. 13 Dec. (1968) 325 Ka appears some days later. James for a weekend... But some (e.g. Ka and Margery) will not overlap; so there'll not be too much of a crowd. 1971Nature 22 Oct. 509/2 The Rothschild inquiry and the Dainton inquiry overlap only at the edges. 1977K. O'Hara Ghost of T. Penry viii. 65 The generations overlapped because the Binns were an enormous family.
c. trans. in causal sense.
1846Greener Sc. Gunnery 149 As a brazier would overlap the edge of a tin pipe, for boys to blow peas with.
†d. Fencing. (absol.) ? To cross one's own blade over one's adversary's. Obs.
1692Sir W. Hope Fencing-Master 71 When you overlapp, do it with the broad side of your blade, and not with the Edge.
2. To cover and extend beyond (lit. and fig.).
1802Paley Nat. Theol. xvi. §4. 301 The upper bill of the parrot is so much hooked, and so much overlaps the lower, that [etc.]. 1853Kane Grinnell Exp. xxii. (1856) 175 The plantigrade base of support overlapped by long hair heightens the resemblance. 1875J. F. Clarke in N. Amer. Rev. CXX. 48 A demand which continually overlapped the supply. 1879Dixon Windsor I. xxiv. 246 He perceived the enemy overlapped and covered by his mighty host.
3. Geol. Said of a newer formation which extends beyond the area or edge of the older one on which it mainly rests, and thus partly overlies a still older one below that. trans. with either of the lower formations as obj. (= sense 1 or 2), or absol.
1832H. T. De la Beche Geol. Man. 265 The great European sheet of chalk and green sand, produced at the cretaceous epoch..overlapped a great variety of pre-existing rocks from the gneiss of Sweden to the Wealden deposits of south-eastern England inclusive. 1871Lyell Elem. Geol. v. 72 Overlapping strata.—Strata are said to overlap, when the upper bed extends beyond the limits of a lower one. 1885Ibid. v. 69 Sediment spread over a region of subsidence has the area of deposit gradually increased, and the newest formed strata will overlap the next below them.
4. To ‘lap’ or ripple over (see lap v.1 4, 5).
1863A. C. Ramsay Phys. Geog. xxxiv. (1878) 581 It has been so largely overlapped and worn away by succeeding waves of Celtic invasion. 1872Browning Fifine lxxxi. 24 No lift of ripple to o'erlap Keel, much less, prow.
Hence overˈlapping ppl. a.
1849Freeman Archit. i. i. i. 37 Overlapping stones cut into the semblance of an arched form. 1869Gillmore Reptiles & Birds i. 7 The surface of the body is..smoothly covered with overlapping scales. 1871[see 3 above]. 1926–7Army & Navy Stores Catal. 854/3 Golfing requisites..Harry Varden's own overlapping grip. Each 4/6. 1958Jrnl. Social Issues XIV. i. 39 A major research question in changing attitudes and behavior is involved in this issue of overlapping situations. 1964Language XL. 62 This instance of overlapping phonetic values therefore need not be regarded as a violation of phonemic principles. 1971Brit. Med. Bull. XXVII. 7/1 According to the theory of overlapping population distribution, the population screened is comprised of a diseased and a non⁓diseased group, both of whom possess the attribute being measured, though with different frequencies at various test levels. 1977New Yorker 10 Oct. 124/2 A certain touring professional golfer barely missed equalling the record for fewest putts in a tournament round by a man using the ordinary overlapping (as opposed to the more popular reverse overlapping) grip. 1978A. Price '44 Vintage ix. 103 The flick-knife was held, for the upwards [blow]..which came in under the overlapping ribs. |