the great circle formed by the intersection of the plane of the earth's orbit with the celestial sphere; the apparent annual path of the sun in the heavens.
b.
an analogous great circle on a terrestrial globe.
2.
Astrology. the great circle of the ecliptic, along which are located the 12 houses and signs of the zodiac.
–adjective Also, e·clip·ti·cal.
3.
pertaining to an eclipse.
4.
pertaining to the ecliptic.
[Origin: 1350–1400; ME < ML eclīptica, fem. of eclīpticus < Gk ekleiptikós, equiv. to ekleíp(ein) (see eclipse) + -tikos-tic]
The intersection plane of the earth's orbit with the celestial sphere, along which the sun appears to move as viewed from the earth.
A great circle inscribed on a terrestrial globe inclined at an approximate angle of 23°27' to the equator and representing the apparent motion of the sun in relation to the earth during a year.
[Middle English ecliptik, from Medieval Latin (līnea) eclīptica, ecliptic (line), from Latin eclīpticus, of an eclipse, from Greek ekleiptikos, from ekleipein, to fail to appear; see eclipse.]
the great circle representing the apparent annual path of the sun; the plane of the Earth's orbit around the sun; makes an angle of about 23 degrees with the equator; "all of the planets rotate the sun in approximately the same ecliptic"
eclipticAudio Help (ĭ-klĭp'tĭk) Pronunciation Key
The great circle on the celestial sphere that represents the Sun's apparent path among the background stars in one year. The northernmost point this path reaches on the celestial sphere is the Tropic of Cancer, its southernmost point is the Tropic of Capricorn, and it crosses the celestial equator at the points of vernal and autumnal equinox. ◇ The plane of the ecliptic is the imaginary plane that intersects the celestial sphere along the ecliptic, and the north and south ecliptic poles are the points where a perpendicular line through the middle of this plane intersect the sphere. The plane of the ecliptic corresponds to the plane in which the Earth orbits the Sun. If the Earth's axis were not tilted, the ecliptic would be identical to the celestial equator and the ecliptic poles identical to the celestial poles. In this case, the Sun's path would not move northward or southward from the equator during the year. As it is, the plane of the celestial equator is tilted 23.45° to the plane of the ecliptic, corresponding to the tilt of the Earth's axis with respect to its orbital plane, giving the Sun its apparent northward and southward movement among the background stars. See illustration at celestial sphere.
Ax"is\, n.; pl. Axes. [L. axis axis, axle. See Axle.] A straight line, real or imaginary, passing through a body, on which it revolves, or may be supposed to revolve; a line passing through a body or system around which the parts are symmetrically arranged. 2. (Math.) A straight line with respect to which the different parts of a magnitude are symmetrically arranged; as, the axis of a cylinder, i. e., the axis of a cone, that is, the straight line joining the vertex and the center of the base; the axis of a circle, any straight line passing through the center. 3. (Bot.) The stem; the central part, or longitudinal support, on which organs or parts are arranged; the central line of any body. --Gray. 4. (Anat.) (a) The second vertebra of the neck, or vertebra dentata. (b) Also used of the body only of the vertebra, which is prolonged anteriorly within the foramen of the first vertebra or atlas, so as to form the odontoid process or peg which serves as a pivot for the atlas and head to turn upon. 5. (Crystallog.) One of several imaginary lines, assumed in describing the position of the planes by which a crystal is bounded. 6. (Fine Arts) The primary or secondary central line of any design. Anticlinal axis (Geol.), a line or ridge from which the strata slope downward on the two opposite sides. Synclinal axis, a line from which the strata slope upward in opposite directions, so as to form a valley. Axis cylinder (Anat.), the neuraxis or essential, central substance of a nerve fiber; -- called also axis band, axial fiber, and cylinder axis. Axis in peritrochio, the wheel and axle, one of the mechanical powers. Axis of a curve (Geom.), a straight line which bisects a system of parallel chords of a curve; called a principal axis, when cutting them at right angles, in which case it divides the curve into two symmetrical portions, as in the parabola, which has one such axis, the ellipse, which has two, or the circle, which has an infinite number. The two axes of the ellipse are the major axis and the minor axis, and the two axes of the hyperbola are the transverse axis and the conjugate axis. Axis of a lens, the straight line passing through its center and perpendicular to its surfaces. Axis of atelescope or microscope, the straight line with which coincide the axes of the several lenses which compose it. Axes of co["o]rdinates in a plane, two straight lines intersecting each other, to which points are referred for the purpose of determining their relative position: they are either rectangular or oblique. Axes of co["o]rdinates in space, the three straight lines in which the co["o]rdinate planes intersect each other. Axis of a balance, that line about which it turns. Axis of oscillation, of a pendulum, a right line passing through the center about which it vibrates, and perpendicular to the plane of vibration. Axis of polarization, the central line around which the prismatic rings or curves are arranged. --Brewster. Axis of revolution (Descriptive Geom.), a straight line about which some line or plane is revolved, so that the several points of the line or plane shall describe circles with their centers in the fixed line, and their planes perpendicular to it, the line describing a surface of revolution, and the plane a solid of revolution. Axis of symmetry (Geom.), any line in a plane figure which divides the figure into two such parts that one part, when folded over along the axis, shall coincide with the other part. Axis of theequator, ecliptic, horizon (or other circle considered with reference to the sphere on which it lies), the diameter of the sphere which is perpendicular to the plane of the circle. --Hutton. Axis of the Ionic capital (Arch.), a line passing perpendicularly through the middle of the eye of the volute. Neutral axis (Mech.), the line of demarcation between the horizontal elastic forces of tension and compression, exerted by the fibers in any cross section of a girder. Optic axis of a crystal, the direction in which a ray of transmitted light suffers no double refraction. All crystals, not of the isometric system, are either uniaxial or biaxial. Optic axis, Visual axis (Opt.), the straight line passing through the center of the pupil, and perpendicular to the surface of the eye. Radical axis of two circles (Geom.), the straight line perpendicular to the line joining their centers and such that the tangents from any point of it to the two circles shall be equal to each other. Spiral axis (Arch.), the axis of a twisted column drawn spirally in order to trace the circumvolutions without. Axis of abscissas and Axis of ordinates. See Abscissa.
E*clip"tic\, n. [Cf. F. ['e]cliptique, L. linea ecliptica, Gr. ?, prop. adj., of an eclipse, because in this circle eclipses of the sun and moon take place. See Ecliptic, a.]1. (Astron.) A great circle of the celestial sphere, making an angle with the equinoctial of about 23[deg] 28'. It is the apparent path of the sun, or the real path of the earth as seen from the sun. 2. (Geog.) A great circle drawn on a terrestrial globe, making an angle of 23[deg] 28' with the equator; -- used for illustrating and solving astronomical problems.
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