| 释义 |
▪ I. arc, n.|ɑːk|
Forms: 4–7 ark(e, 6 arcke, 6– arc.
[a. OF. arc:—L. arcum (nom. arcus) bow, arch, curve.]
1. a. Part of the circumference of a circle or other curve.
1570Billingsley Euclid iii. Introd., Right lines subtended to arkes in circles. 1750Phil. Trans. XLVII. 64 Any arc described by the revolving body. 1871C. Davies Metric Syst. i. 18 The French Government..measured a degree of the arc of a meridian on the earth's surface.
b. transf. or fig.
1643Milton Divorce vi. (1851) 33 One of the highest arks that human contemplation circling upwards, can make. 1805Southey Madoc in Azt. vii, The Britons shrunk Beyond its arc of motion. 1871Tyndall Fragm. Sc. II. vii. 97 The circle of human nature, then, is not complete without the arc of the emotions.
2. spec. in Astr. The part of a circle which a heavenly body appears to pass through above (diurnal arc) or below (nocturnal arc) the horizon. The earliest use in Eng. Also fig.
c1386Chaucer Merch. T. 551 Parfourmed hath the sonne his ark diourne. c1391― Astrol. ii. vii, Tak ther thin ark of the day. The remenant of the bordure vnder the Orisonte is the ark of the nyht. c1430Lydg. Bochas i. xx. (1554) 39 a, As faire as Phebus shineth in his arke. c1590Marlowe 2nd Pt. Tamburl. iii. ii, The stars fix'd in the Southern arc. 1787Bonnycastle Astron. 428 Nocturnal arc is that space of the heavens which the sun apparently describes from the time of his setting to the time of his rising. 1878Geo. Eliot Coll. Breakf. P. 572 Say, the small arc of Being we call man Is near its mergence.
3. A band or belt contained between parallel curves; anything presenting this form optically or superficially, e.g. the rainbow (F. arc-en-ciel), the brass arc of a quadrant on which the degrees are marked off, etc.
1642H. More Song of Soul ii. i. iii. xx, The higher causes of that coloured Ark. 1768Wales in Phil. Trans. LX. 120 The quadrant..we found much tarnished, especially the arc. 1831Brewster Newton (1855) I. vii. 161 He describes the arcs and circles of colours.
†4. An arch. (Cf. Fr. arc de triomphe.) Obs.
1563Shute Archit. E iiij a, The arke triumphant of Seuerus. 1671Milton P.R. iv. 37 Statues and Trophees, and Triumphal Arcs. 1731Pope Mor. Ess. ii. 30 Turn arcs of triumph to a garden-gate.
5. Electr. The luminous bridge formed between two carbon poles, when they are separated by a small air space, and a powerful current of electricity is sent through them. Often attrib.
1821Sir H. Davy in Phil. Trans. 427 The poles were connected by charcoal so as to make an arc, or column of electrical light. 1894Phil. Trans. R. Soc. A. CLXXXV. 983 The photographic arc spectrum of electrolytic iron. 1900Jrnl. Soc. Arts XLVIII. 820/1 The multiple arc furnace..has lately become much used, because it enables the area of arc heating to be greatly extended. 1935Discovery Sept. 260/2 The appearance in the arc-spectrum of the ‘raies ultimes’ of copper at λ 3274 and λ 3248 completed the identification of the pigment. 1940Chambers's Techn. Dict. 47/1 Arc furnace, an electric furnace in which the heat is produced by means of an electric arc between carbon electrodes, or between a carbon electrode and the furnace charge. Ibid. 47/2 Arc spectrum, a spectrum originating in the non-ionised atoms of an element; usually capable of being excited by the application of a comparatively low stimulus, such as the electric arc. 1946Nature 2 Nov. 631/1 Faulty power lines which are maintained in operation through the use of arc-suppression coils. 1956Ibid. 28 Jan. 157/2 Resistance-type (calrod) heaters embedded in the cast-copper charge oven and arc-chamber support block.
6. transf. in Phys. Circuit, round.
1855H. Spencer Psychol. (1872) I. i. ii. 42 The nervous arc..consists of the afferent nerve..the ganglion corpuscle to which its central extremity runs, and the efferent nerve thence issuing.
▸ orig. Literary Criticism. The principal plot or narrative development of a literary or dramatic work considered in outline form. Now also: spec. (freq. in story arc) a background plot or ongoing storyline in a serial narrative (esp. a television series), within which self-contained episodes are set; an episode or number of episodes which develop such a background story.
1962F. N. Mennemeier in P. Demetz Brecht 148 There is no ‘great dramatic arc’ in Mother Courage... In Brecht's play there is an artfully static structure which carefully balances individual scenes against each other. 1978G. Stewart in ELH 45 483 In the proliferated death scenes of Bleak House, Dickens brings death as never before into the pages that intervene between the implied oblivion before and after the arc of story, the unvoiced voids of narrative. 1986M. Stephens Dramaturgy of Style ix. 229 Very often Stephen Dixon's first-person narrator is not central, though remaining crucial and important, to the dramatic arc. 1995C. Carter Truth is out There 88 Lea was the only actor considered in Vancouver for the part, which he thought would simply be a three-episode arc. 2001Dreamwatch Mar. 62/4 With the third series of First Wave nearing completion, Brancato says the overall story arc is pretty much locked down at this point.
▪ II. arc, v.|ɑːk|
Inflected arced, arcing (with c pronounced k).
[f. arc n.]
1. intr. To form an electric arc. So ˈarcing vbl. n.
1893Westm. Gaz. 20 June 6/3 In ‘arcing’ or jumping from one conductor to another the current damaged the [gas] pipes. 1905Daily Chron. 19 Apr. 6/5 The contact or arcing between the telephone cables and the conductor rail. 1908Installation News II. 19/2 The fuse is provided with a phosphor bronze arcing tongue. 1910Ibid. IV. 63/1 Fires..due to the melting of soft compo gas-pipe, by arcing. 1943Gloss. Terms Electr. Engineering (B.S.I.) 59 Arcing contacts, contacts which open after and close before the main contacts to protect the latter from injury by an arc.
2. To move or fly in an arc.
1954J. Christopher 22nd Cent. 116 Bouncing round in three complete circuits before arcing down to land. 1961Guardian 4 May 4/2 The rocket arc-ed majestically into the cloudless sky.
▪ III. arc
obs. form of ark. |