the line about which a rotating body, such as the earth, turns.
2.
Mathematics.
a.
a central line that bisects a two-dimensional body or figure.
b.
a line about which a three-dimensional body or figure is symmetrical.
3.
Anatomy.
a.
a central or principal structure, about which something turns or is arranged: the skeletal axis.
b.
the second cervical vertebra.
4.
Botany. the longitudinal support on which organs or parts are arranged; the stem and root; the central line of any body.
5.
Analytic Geometry. any line used as a fixed reference in conjunction with one or more other references for determining the position of a point or of a series of points forming a curve or a surface. Compare x-axis, y-axis.
Aeronautics. any one of three lines defining the attitude of an airplane, one being generally determined by the direction of forward motion and the other two at right angles to it and to each other.
8.
Fine Arts. an imaginary line, in a given formal structure, about which a form, area, or plane is organized.
9.
an alliance of two or more nations to coordinate their foreign and military policies, and to draw in with them a group of dependent or supporting powers.
10.
the Axis, (in World War II) Germany, Italy, and Japan, often with Bulgaria, Hungary, and Romania.
11.
a principal line of development, movement, direction, etc.
[Origin: 1540–50; < L axis an axletree, axle, axis. See axi-]
A straight line about which a body or geometric object rotates or may be conceived to rotate.
Mathematics
An unlimited line, half-line, or line segment serving to orient a space or a geometric object, especially a line about which the object is symmetric.
A reference line from which distances or angles are measured in a coordinate system.
The second cervical vertebra on which the head turns.
Any of various central structures, such as the spinal column, or standard abstract lines used as a positional referent.
An alliance of powers, such as nations, to promote mutual interests and policies.
Axis The alliance of Germany and Italy in 1936, later including Japan and other nations, that opposed the Allies in World War II.
A center line to which parts of a structure or body may be referred.
An imaginary line to which elements of a work of art, such as a picture, are referred for measurement or symmetry.
Anatomy
The second cervical vertebra on which the head turns.
Any of various central structures, such as the spinal column, or standard abstract lines used as a positional referent.
An alliance of powers, such as nations, to promote mutual interests and policies.
Axis The alliance of Germany and Italy in 1936, later including Japan and other nations, that opposed the Allies in World War II.
Botany The main stem or central part about which organs or plant parts such as branches are arranged.
One of three mutually perpendicular lines that define the orientation of an aircraft, with one being along its direction of travel and the other two being perpendicular to the direction of travel.
A line through the optical center of a lens that is perpendicular to both its surfaces.
One of three or four imaginary lines used to define the faces of a crystal and the position of its atoms.
An alliance of powers, such as nations, to promote mutual interests and policies.
Axis The alliance of Germany and Italy in 1936, later including Japan and other nations, that opposed the Allies in World War II.
1549, "imaginary straight line around which a body (such as the Earth) rotates," from L. axis "axle, pivot, axis of the earth or sky," from PIE *aks- "axis" (cf. O.E. eax, O.H.G. ahsa "axle," Gk. axon, Skt. aksah "an axle, axis, beam of a balance," Lith. aszis). Fig. sense in world history of "alliance between Germany and Italy" (later extended to include Japan) is from 1936.
An imaginary line around which an object rotates. In a rotating sphere, such as the Earth and other planets, the two ends of the axis are called poles. The 23.45° tilt of the Earth's axis with respect to the plane of its orbit around the Sun causes the Northern and Southern Hemispheres to point toward and away from the Sun at different times of the year, creating seasonal patterns of weather and climate. Other planets in the solar system have widely varying tilts to their axes, ranging from near 0° for Mercury to 177° for Venus.
Mathematics
A line, ray, or line segment with respect to which a figure or object is symmetrical.
A reference line from which distances or angles are measured in a coordinate system, such as the x-axis and y-axis in the Cartesian coordinate system.
Anatomy The second cervical vertebra, which serves as a pivot for the head.
Botany The main stem or central part of a plant or plant part, about which other plant parts, such as branches or leaflets, are arranged.
Main Entry: ax·is Pronunciation: 'ak-s&s Function: noun Inflected Form: pluralax·es/-"sEz/ 1 a: a
straight line about which a body or a geometric figure rotates or may be thought of as rotating b: a straight line with respect to which a body, organ, or figure is symmetrical 2 a: the second vertebra of the neck of the higher vertebrates that is prolonged anteriorly within the foramen of the first vertebra and united with the dens which serves as a pivot
for the atlas and head to turn upon called also epistropheusb: any of various central, fundamental, or axial parts <the cerebrospinal axis> <the skeletal
axis> c:AXILLA
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.
Ax"le\ ([a^]ks"'l), n. [OE. axel, exel, shoulder, AS. eaxl; akin to AS. eax axle, Sw. & Dan. axel shoulder, axle, G. achse axle, achsel shoulder, L. axis axle, Gr. 'a`xwn, Skr. aksha, L. axilla shoulder joint: cf. F. essieu, axle, OF. aissel, fr. dim. of L. axis. [root]205. Cf. 2d Axis.]1. The pin or spindle on which a wheel revolves, or which revolves with a wheel. 2. A transverse bar or shaft connecting the opposite wheels of a car or carriage; an axletree. 3. An axis; as, the sun's axle. Had from her axle torn The steadfast earth. --Milton. Note: Railway axles are called leading and trailing from their position in the front or in the rear of a car or truck respectively.
Curve\, n. [See Curve, a., Cirb.]1. A bending without angles; that which is bent; a flexure; as, a curve in a railway or canal. 2. (Geom.) A line described according to some low, and having no finite portion of it a straight line. Axis of a curve. See under Axis. Curve of quickest descent. See Brachystochrone. Curve tracing (Math.), the process of determining the shape, location, singular points, and other peculiarities of a curve from its equation. Plane curve (Geom.), a curve such that when a plane passes through three points of the curve, it passes through all the other points of the curve. Any other curve is called a curve of double curvature, or a twisted curve.
Cyl"in*der\ (s?l"?n-d?r), n. [F. cylindre, OF. cilindre, L. cylindrus, fr. Gr. ky`lindros, fr. kyli`ndein, kyli`ein, to roll. Cf. Calender the machine.]1. (Geom.) (a) A solid body which may be generated by the rotation of a parallelogram round one its sides; or a body of rollerlike form, of which the longitudinal section is oblong, and the cross section is circular. (b) The space inclosed by any cylindrical surface. The space may be limited or unlimited in length. 2. Any hollow body of cylindrical form, as: (a) The chamber of a steam engine in which the piston is moved by the force of steam. (b) The barrel of an air or other pump. (c) (Print.) The revolving platen or bed which produces the impression or carries the type in a cylinder press. (d) The bore of a gun; the turning chambered breech of a revolver. 3. The revolving square prism carrying the cards in a Jacquard loom. Cylinder axis. (Anat.) See Axis cylinder, under Axis. Cylinder engine (Paper Making), a machine in which a cylinder takes up the pulp and delivers it in a continuous sheet to the dryers. Cylinder escapement. See Escapement. Cylinder glass. See Glass. Cylinder mill. See Roller mill. Cylinder press. See Press.
Deer\ (d[=e]r), n. sing. & pl. [OE. der, deor, animal, wild animal, AS. de['o]r; akin to D. dier, OFries. diar, G. thier, tier, Icel. d[=y]r, Dan. dyr, Sw. djur, Goth. dius; of unknown origin. [root]71.]1. Any animal; especially, a wild animal. [Obs.] --Chaucer. Mice and rats, and such small deer. --Shak. The camel, that great deer. --Lindisfarne MS. 2. (Zo["o]l.) A ruminant of the genus Cervus, of many species, and of related genera of the family Cervid[ae]. The males, and in some species the females, have solid antlers, often much branched, which are shed annually. Their flesh, for which they are hunted, is called venison. Note: The deer hunted in England is Cervus elaphus, called also stag or red deer; the fallow deer is C. dama; the common American deer is C. Virginianus; the blacktailed deer of Western North America is C. Columbianus; and the mule deer of the same region is C. macrotis. See Axis, Fallow deer, Mule deer, Reindeer. Note: Deer is much used adjectively, or as the first part of a compound; as, deerkiller, deerslayer, deerslaying, deer hunting, deer stealing, deerlike, etc. Deer mouse (Zo["o]l.), the white-footed mouse (Hesperomys leucopus) of America. Small deer, petty game, not worth pursuing; -- used metaphorically. (See citation from Shakespeare under the first definition, above.) "Minor critics . . . can find leisure for the chase of such small deer." --G. P. Marsh.
In`ter*ax"is\, n.; pl. Interaxes. (Arch.) The space between two axes. See Axis, 6. The doors, windows, niches, and the like, are then placed centrally in the interaxes. --Gwilt.
Neu"tral\, a. [L. neutralis, fr. neuter. See Neuter.]1. Not engaged on either side; not taking part with or assisting either of two or more contending parties; neuter; indifferent. The heart can not possibly remain neutral, but constantly takes part one way or the other. --Shaftesbury. 2. Neither good nor bad; of medium quality; middling; not decided or pronounced. Some things good, and some things ill, do seem, And neutral some, in her fantastic eye. --Sir J. Davies. 3. (Biol.) Neuter. See Neuter, a., 3. 4. (Chem.) Having neither acid nor basic properties; unable to turn red litmus blue or blue litmus red; -- said of certain salts or other compounds. Contrasted with acid, and alkaline. Neutral axis, Neutral surface (Mech.), that line or plane, in a beam under transverse pressure, at which the fibers are neither stretched nor compressed, or where the longitudinal stress is zero. See Axis. Neutral equilibrium (Mech.), the kind of equilibrium of a body so placed that when moved slighty it neither tends to return to its former position not depart more widely from it, as a perfect sphere or cylinder on a horizontal plane. Neutral salt (Chem.), a salt formed by the complete replacement of the hydrogen in an acid or base; in the former case by a positive or basic, in the latter by a negative or acid, element or radical. Neutral tint, a bluish gray pigment, used in water colors, made by mixing indigo or other blue some warm color. the shades vary greatly. Neutral vowel, the vowel element having an obscure and indefinite quality, such as is commonly taken by the vowel in many unaccented syllables. It is regarded by some as identical with the [u^] in up, and is called also the natural vowel, as unformed by art and effort. See Guide to Pronunciation, [sect] 17.
O*don"toid\, a. [Gr. ?; 'odoy`s, 'odo`ntos, a tooth + ? form: cf.F. odonto["i]de.] (Anat.) (a) Having the form of a tooth; toothlike. (b) Of or pertaining to the odontoid bone or to the odontoid process. Odontoid bone (Anat.), a separate bone, in many reptiles, corresponding to the odontoid process. Odontoid process, or Odontoid peg (Anat.), the anterior process of the centrum of the second vertebra, or axis, in birds and mammals. See Axis.
Os`cil*la"tion\, n. [L. oscillatio a swinging.]1. The act of oscillating; a swinging or moving backward and forward, like a pendulum; vibration. 2. Fluctuation; variation; change back and forth. His mind oscillated, undoubtedly; but the extreme points of the oscillation were not very remote. --Macaulay. Axis of oscillation, Center of oscillation. See under Axis, and Center.
Per`i*tro"chi*um\, n. [NL., fr. Gr. ?; ? around + ? a wheel.] (Mech.) The wheel which, together with the axle, forms the axis in peritrochio, which see under Axis.
Prin"ci*pal\, a. [F., from L. principalis. See Prince.]1. Highest in rank, authority, character, importance, or degree; most considerable or important; chief; main; as, the principal officers of a Government; the principal men of a state; the principal productions of a country; the principal arguments in a case. Wisdom is the principal thing. --Prov. iv. 7. 2. Of or pertaining to a prince; princely. [A Latinism] [Obs.] --Spenser. Principal axis. See Axis of a curve, under Axis. Principal axes of a quadric (Geom.), three lines in which the principal planes of the solid intersect two and two, as in an ellipsoid. Principal challenge. (Law) See under Challenge. Principal plane. See Plane of projection (a), under Plane. Principal of a quadric (Geom.), three planes each of which is at right angles to the other two, and bisects all chords of the quadric perpendicular to the plane, as in an ellipsoid. Principal point (Persp.), the projection of the point of sight upon the plane of projection. Principal ray (Persp.), the line drawn through the point of sight perpendicular to the perspective plane. Principal section (Crystallog.), a plane passing through the optical axis of a crystal.
Rad"i*cal\, a. [F., fr. L. radicalis having roots, fr. radix, -icis, a root. See Radix.]1. Of or pertaining to the root; proceeding directly from the root. 2. Hence: Of or pertaining to the root or origin; reaching to the center, to the foundation to the ultimate sources to the principles, or the like: original; fundamental; thorough-going; unsparing; extreme; as, radical evils; radical reform; a radical party. The most determined exertions of that authority, against them, only showed their radical independence. --Burke. 3. (Bot.) (a) Belonging to, or proceeding from, the root of a plant; as, radical tubers or hairs. (b) Proceeding from a rootlike stem, or one which does not rise above the ground; as, the radical leaves of the dandelion and the sidesaddle flower. 4. (Philol.) Relating, or belonging, to the root, or ultimate source of derivation; as, a radical verbal form. 5. (Math.) Of or pertaining to a radix or root; as, a radical quantity; a radical sign. See below. Radical axis of two circles. (Geom.) See under Axis. Radical pitch, the pitch or tone with which the utterance of a syllable begins. --Rush. Radical quantity (Alg.), a quantity to which the radical sign is prefixed; specifically, a quantity which is not a perfect power of the degree indicated by the radical sign; a surd. Radical sign (Math.), the sign [root] (originally the letter r, the initial of radix, root), placed before any quantity, denoting that its root is to be extracted; thus, [root]a, or [root](a + b). To indicate any other than the square root, a corresponding figure is placed over the sign; thus [cuberoot]a, indicates the third or cube root of a. Radical stress (Elocution), force of utterance falling on the initial part of a syllable or sound. Radical vessels (Anat.), minute vessels which originate in the substance of the tissues. Syn: Primitive; original; natural; underived; fundamental; entire. Usage: Radical, Entire. These words are frequently employed as interchangeable in describing some marked alternation in the condition of things. There is, however, an obvious difference between them. A radical cure, reform, etc., is one which goes to the root of the thing in question; and it is entire, in the sense that, by affecting the root, it affects in a appropriate degree the entire body nourished by the root; but it may not be entire in the sense of making a change complete in its nature, as well as in its extent. Hence, we speak of a radical change; a radical improvement; radical differences of opinion; while an entire change, an entire improvement, an entire difference of opinion, might indicate more than was actually intended. A certain change may be both radical and entire, in every sense.
Sym"me*try\, n. [L. symmetria, Gr. ?; sy`n with, together + ? a measure: cf. F. sym['e]trie. See Syn-, and Meter rhythm.]1. A due proportion of the several parts of a body to each other; adaptation of the form or dimensions of the several parts of a thing to each other; the union and conformity of the members of a work to the whole. 2. (Biol.) The law of likeness; similarity of structure; regularity in form and arrangement; orderly and similar distribution of parts, such that an animal may be divided into parts which are structurally symmetrical. Note: Bilateral symmetry, or two-sidedness, in vertebrates, etc., is that in which the body can be divided into symmetrical halves by a vertical plane passing through the middle; radial symmetry, as in echinoderms, is that in which the individual parts are arranged symmetrically around a central axis; serial symmetry, or zonal symmetry, as in earthworms, is that in which the segments or metameres of the body are disposed in a zonal manner one after the other in a longitudinal axis. This last is sometimes called metamerism. 3. (Bot.) (a) Equality in the number of parts of the successive circles in a flower. (b) Likeness in the form and size of floral organs of the same kind; regularity. Axis of symmetry. (Geom.) See under Axis. Respective symmetry, that disposition of parts in which only the opposite sides are equal to each other.
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