octantn.

Brit.

/ˈɒkt(ə)nt/, U.S.

/ˈɑkt(ə)nt/

Origin: A borrowing from Latin. Etymons: Latin octant-, octāns.

Etymology: < classical Latin octant-, octāns eighth part of a circle (Vitruvius) < octo eight (see octo- comb. form) + -āns (in quadrāns quadrant n.¹). Compare French octant (1683 denoting the aspect of a planet which is 45° from another, 1761 (citing an earlier text) denoting an instrument like a sextant, 1803 as the name of a constellation, 1874 in sense ‘arc of 45°’).

a. An instrument in the form of a graduated eighth of a circle, formerly used for making angular measurements esp. in astronomy and navigation.

ΘΚΠ

the world > the universe > cosmology > science of observation > astronomical instruments > [noun] > other

volvelle1501

semicircle1594

octant1672

panorganon1672

Antikythera mechanism1959

1672 Philos. Trans. (Royal Soc.) 7 4017 I intend to send you by the next more particular and more accurate Observations, which I purpose to make carefully, as oft as I can, with my Brass Octant, which is about 9 feet long.

1732 Philos. Trans. 1731–2 (Royal Soc.) 37 150 The Instrument consists of an Octant ABC, having on its Limb BC an Arch of 45 Degrees, divided into 90 Parts or half Degrees.

1774 M. Mackenzie Treat. Maritim Surv. 2 The principal Instruments used in surveying; such as the Theodolite, the astronomical Quadrant, and Hadley's Octant, or Sextant.

1825 ‘J. Nicholson’ Operative Mechanic 316 Binding himself to divide all sextants and octants by the same engine.

1988 Jrnl. Navigation 41 320 The marine sextant had first appeared in the middle of the previous century (1757), having evolved from earlier instruments, chiefly the octant and the measuring circle.

1990 A. Chapman Dividing Circle viii. 126 Smeaton relates that it had been one of Hindley's hopes that the engine would be sufficiently trustworthy for the graduation of the new Hadley octants to merit an official reward.

b. Astronomy. the Octant: (the English name of) the constellation Octans. Chiefly as a conscious translation.

ΚΠ

1842 Mem. Royal Astron. Soc. 12 204 The Quadrant, the Sextant, and the Octant, as names for three distinct constellations.

1910 Encycl. Brit. VII. 14/1 Octans (Octant).

1990 P. S. Harrington Touring Universe through Binoculars vii. 184 Home of the south celestial pole, the constellation Octans, the Octant, was first mentioned by Lacaille in 1752.

2. Astronomy and †Astrology. The aspect of a planet which is one-eighth of a circle (45°) apart in the sky from another planet, from the sun, or from some particular point; spec. each of the four points at which the moon is 45° from conjunction with or opposition to the sun, or midway between the syzygies and quadratures. Cf. octile adj. and n. Now rare.

ΘΚΠ

the world > the universe > planet > primary planet > moon > lunar orbit > [noun] > octant

octant1687

octile1690

1687 W. Molyneux Let. 12 Feb. in J. Flamsteed Corr. (1997) II. 334 But doe not mistake me I doe not thinke the strongest Impulses made at the New and full Moones. I have above 100 observations by me that will rather fix them on the octants. and yet the greatest Inequalitys are neather on those pointes nor the Suzigia nor Quadratures.

1690 W. Leybourn Cursus mathematicus f. 773 About the octants from the aphelion and perihelion.

1706 Phillips's New World of Words (new ed.) Octant or Octile (in Astrol.), when a planet is in such an aspect or position with respect to another, that their places are only distant an eighth part of a circle, or 45 degrees.

1747 Philos. Trans. (Royal Soc.) 44 414 I compared the theory of the moon, as to her longitude, with several observations, as well in the octants and semi-octants, as in the syzygies and quadratures.

1786 J. Bonnycastle Introd. Astron. 356 When she comes to her first octant..a quarter of her enlightened hemisphere will be turned towards the earth.

1834 Hist. Astron. (U.K.S.) ix. 45/1 A third [inequality of the moon], called the variation,..is greatest in the octants.

1967 Isis 58 36 If he had happened to observe the moon at the node and in an octant, he could have found a discrepancy of several minutes.

1994 J. North Fontana Hist. Astron. & Cosmol. xii. 306 He settled on the octants, mid-way between syzygies and quadratures, and observed the Moon carefully through these points.

a. Each of eight parts into which a space or solid figure is divided by three planes (usually mutually perpendicular) intersecting at the central point.

ΘΚΠ

the world > relative properties > wholeness > incompleteness > part of whole > [noun] > one of the parts into which anything is divided > one of eight

octodrant1688

octant1737

the world > relative properties > number > specific numbers > eight > [noun] > division into eight > an eighth > made by three intersecting planes

octant1737

1737 Philos. Trans. 1735–6 (Royal Soc.) 39 205 Now the same Conveniencies that may be derived from the whole Globe, may, in Proportion, be had from any notable Portions of it; as an Hemisphere, a Quadrant, a Sectant, an Octant, or other Part.

1791 Philos. Trans. 1790 (Royal Soc.) 80 497 Disposed in the eight octants of a regular parallelopipedon.

1875 A. W. Bennett & W. T. T. Dyer tr. J. von Sachs Text-bk. Bot. 288 The globule [i.e. the antheridium of Nitella] now consists of four lower and four upper octants of a sphere... Each octant now breaks up..into an outer and an inner cell.

1895 N. Story-Maskelyne Crystallogr. ii. §15 These planes..divide the space round the origin into eight hollow quoins or octants.

1945 W. O. Howarth & L. G. G. Warne Lowson's Textbk. Bot. (ed. 9) xi. 268 The embryonal cell now divides by three walls at right angles into eight cells (octants).

1982 V. N. McIntyre Wrath of Khan iv. 92 But we're the only ship free in the octant.

b. An arc of a circle or of the horizon forming one-eighth of the whole; one-eighth of the area of a circle, contained within two radii at an angle of 45°.

ΘΚΠ

the world > relative properties > number > geometry > curve > [noun] > part of circle

arc1570

sextans1596

circumference1656

quadrant1660

quintant1684

sextant1730

octant1753

supplemental arc1754

multiple arc1802

explement1817

the world > relative properties > number > geometry > shape or figure > [noun] > two-dimensional > figure forming part of circle

nook cantle1551

quadrate1551

quadrant1559

section1570

sector1570

segment1570

sextant1628

half-round1718

octant1753

1753 Philos. Trans. 1751–2 (Royal Soc.) 47 69 Thro' the whole octant OA, it is continually decreasing.

1876 Philos. Trans. 1875 (Royal Soc.) 165 411 The irregularity of the wind..varies in each octant.

1967 R. W. Fairbridge Encycl. Atmospheric Sci. & Astrogeol. 1147/2 Some eight ‘octants’ (N, NE, E, etc.) are recognized.

1971 Nature 23 Apr. 490/2 A pattern of stripes painted on the edges of alternate octants of a transparent disk.

This entry has been updated (OED Third Edition, March 2004; most recently modified version published online March 2022).

单词	octant
释义	octantn. Brit. /ˈɒkt(ə)nt/, U.S. /ˈɑkt(ə)nt/ Origin: A borrowing from Latin. Etymons: Latin octant-, octāns. Etymology: < classical Latin octant-, octāns eighth part of a circle (Vitruvius) < octo eight (see octo- comb. form) + -āns (in quadrāns quadrant n.¹). Compare French octant (1683 denoting the aspect of a planet which is 45° from another, 1761 (citing an earlier text) denoting an instrument like a sextant, 1803 as the name of a constellation, 1874 in sense ‘arc of 45°’). 1. a. An instrument in the form of a graduated eighth of a circle, formerly used for making angular measurements esp. in astronomy and navigation. ΘΚΠ the world > the universe > cosmology > science of observation > astronomical instruments > [noun] > other volvelle1501 semicircle1594 octant1672 panorganon1672 Antikythera mechanism1959 1672 Philos. Trans. (Royal Soc.) 7 4017 I intend to send you by the next more particular and more accurate Observations, which I purpose to make carefully, as oft as I can, with my Brass Octant, which is about 9 feet long. 1732 Philos. Trans. 1731–2 (Royal Soc.) 37 150 The Instrument consists of an Octant ABC, having on its Limb BC an Arch of 45 Degrees, divided into 90 Parts or half Degrees. 1774 M. Mackenzie Treat. Maritim Surv. 2 The principal Instruments used in surveying; such as the Theodolite, the astronomical Quadrant, and Hadley's Octant, or Sextant. 1825 ‘J. Nicholson’ Operative Mechanic 316 Binding himself to divide all sextants and octants by the same engine. 1988 Jrnl. Navigation 41 320 The marine sextant had first appeared in the middle of the previous century (1757), having evolved from earlier instruments, chiefly the octant and the measuring circle. 1990 A. Chapman Dividing Circle viii. 126 Smeaton relates that it had been one of Hindley's hopes that the engine would be sufficiently trustworthy for the graduation of the new Hadley octants to merit an official reward. b. Astronomy. the Octant: (the English name of) the constellation Octans. Chiefly as a conscious translation. ΚΠ 1842 Mem. Royal Astron. Soc. 12 204 The Quadrant, the Sextant, and the Octant, as names for three distinct constellations. 1910 Encycl. Brit. VII. 14/1 Octans (Octant). 1990 P. S. Harrington Touring Universe through Binoculars vii. 184 Home of the south celestial pole, the constellation Octans, the Octant, was first mentioned by Lacaille in 1752. 2. Astronomy and †Astrology. The aspect of a planet which is one-eighth of a circle (45°) apart in the sky from another planet, from the sun, or from some particular point; spec. each of the four points at which the moon is 45° from conjunction with or opposition to the sun, or midway between the syzygies and quadratures. Cf. octile adj. and n. Now rare. ΘΚΠ the world > the universe > planet > primary planet > moon > lunar orbit > [noun] > octant octant1687 octile1690 1687 W. Molyneux Let. 12 Feb. in J. Flamsteed Corr. (1997) II. 334 But doe not mistake me I doe not thinke the strongest Impulses made at the New and full Moones. I have above 100 observations by me that will rather fix them on the octants. and yet the greatest Inequalitys are neather on those pointes nor the Suzigia nor Quadratures. 1690 W. Leybourn Cursus mathematicus f. 773 About the octants from the aphelion and perihelion. 1706 Phillips's New World of Words (new ed.) Octant or Octile (in Astrol.), when a planet is in such an aspect or position with respect to another, that their places are only distant an eighth part of a circle, or 45 degrees. 1747 Philos. Trans. (Royal Soc.) 44 414 I compared the theory of the moon, as to her longitude, with several observations, as well in the octants and semi-octants, as in the syzygies and quadratures. 1786 J. Bonnycastle Introd. Astron. 356 When she comes to her first octant..a quarter of her enlightened hemisphere will be turned towards the earth. 1834 Hist. Astron. (U.K.S.) ix. 45/1 A third [inequality of the moon], called the variation,..is greatest in the octants. 1967 Isis 58 36 If he had happened to observe the moon at the node and in an octant, he could have found a discrepancy of several minutes. 1994 J. North Fontana Hist. Astron. & Cosmol. xii. 306 He settled on the octants, mid-way between syzygies and quadratures, and observed the Moon carefully through these points. 3. a. Each of eight parts into which a space or solid figure is divided by three planes (usually mutually perpendicular) intersecting at the central point. ΘΚΠ the world > relative properties > wholeness > incompleteness > part of whole > [noun] > one of the parts into which anything is divided > one of eight octodrant1688 octant1737 the world > relative properties > number > specific numbers > eight > [noun] > division into eight > an eighth > made by three intersecting planes octant1737 1737 Philos. Trans. 1735–6 (Royal Soc.) 39 205 Now the same Conveniencies that may be derived from the whole Globe, may, in Proportion, be had from any notable Portions of it; as an Hemisphere, a Quadrant, a Sectant, an Octant, or other Part. 1791 Philos. Trans. 1790 (Royal Soc.) 80 497 Disposed in the eight octants of a regular parallelopipedon. 1875 A. W. Bennett & W. T. T. Dyer tr. J. von Sachs Text-bk. Bot. 288 The globule [i.e. the antheridium of Nitella] now consists of four lower and four upper octants of a sphere... Each octant now breaks up..into an outer and an inner cell. 1895 N. Story-Maskelyne Crystallogr. ii. §15 These planes..divide the space round the origin into eight hollow quoins or octants. 1945 W. O. Howarth & L. G. G. Warne Lowson's Textbk. Bot. (ed. 9) xi. 268 The embryonal cell now divides by three walls at right angles into eight cells (octants). 1982 V. N. McIntyre Wrath of Khan iv. 92 But we're the only ship free in the octant. b. An arc of a circle or of the horizon forming one-eighth of the whole; one-eighth of the area of a circle, contained within two radii at an angle of 45°. ΘΚΠ the world > relative properties > number > geometry > curve > [noun] > part of circle arc1570 sextans1596 circumference1656 quadrant1660 quintant1684 sextant1730 octant1753 supplemental arc1754 multiple arc1802 explement1817 the world > relative properties > number > geometry > shape or figure > [noun] > two-dimensional > figure forming part of circle nook cantle1551 quadrate1551 quadrant1559 section1570 sector1570 segment1570 sextant1628 half-round1718 octant1753 1753 Philos. Trans. 1751–2 (Royal Soc.) 47 69 Thro' the whole octant OA, it is continually decreasing. 1876 Philos. Trans. 1875 (Royal Soc.) 165 411 The irregularity of the wind..varies in each octant. 1967 R. W. Fairbridge Encycl. Atmospheric Sci. & Astrogeol. 1147/2 Some eight ‘octants’ (N, NE, E, etc.) are recognized. 1971 Nature 23 Apr. 490/2 A pattern of stripes painted on the edges of alternate octants of a transparent disk. This entry has been updated (OED Third Edition, March 2004; most recently modified version published online March 2022). < n.1672
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