axis

¹

[ ak-sis ]

noun

, plural ax·es [ak, -seez].

1. the line about which a rotating body, such as the earth, turns.
2. Mathematics.
   1. a central line that bisects a two-dimensional body or figure.
   2. a line about which a three-dimensional body or figure is symmetrical.
3. Anatomy.
   1. a central or principal structure, about which something turns or is arranged:

      the skeletal axis.

   2. 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.
6. Crystallography. crystallographic axis.
7. 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.

axis

²

[ ak-sis ]

noun

, plural ax·is·es.

1. axis deer.

Axis

¹

/ ˈæksɪs /

noun

1. 1. the alliance of Nazi Germany, Fascist Italy, and Japan, established in 1936 and lasting until their defeat in World War II
   2. ( as modifier )

      the Axis powers

axis

²

/ ˈæksɪs /

noun

1. any of several S Asian deer of the genus Axis, esp A. axis. They typically have a reddish-brown white-spotted coat and slender antlers

axis

³

/ ˈæksɪs /

noun

1. a real or imaginary line about which a body, such as an aircraft, can rotate or about which an object, form, composition, or geometrical construction is symmetrical
2. one of two or three reference lines used in coordinate geometry to locate a point in a plane or in space
3. anatomy the second cervical vertebra Compare atlas
4. botany the main central part of a plant, typically consisting of the stem and root, from which secondary branches and other parts develop
5. an alliance between a number of states to coordinate their foreign policy
6. Also calledprincipal axis optics the line of symmetry of an optical system, such as the line passing through the centre of a lens
7. geology an imaginary line along the crest of an anticline or the trough of a syncline
8. crystallog one of three lines passing through the centre of a crystal and used to characterize its symmetry

axis

/ ăk′sĭs /

, Plural axes ăk′sēz′

1. 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.
2. Mathematics.
   1. A line, ray, or line segment with respect to which a figure or object is symmetrical.
   2. 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.
3. Anatomy.
   The second cervical vertebra, which serves as a pivot for the head.
4. 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.

axis

¹

1. In geometry , a straight line about which an object may rotate or that divides an object into symmetrical halves.

axis

²

1. An imaginary straight line passing through the North Pole , the center of the Earth , and the South Pole . The Earth rotates around this axis.

Notes

The axis of the Earth is an imaginary line drawn through the North Pole and the South Pole .

Other Words From

• ax·ised [ak, -sist], adjective
• un·axised adjective

Word History and Origins

Origin of axis¹

First recorded in 1350–1400; Middle English; from Latin axis “an axletree, axle, axis”; axi-

Origin of axis²

First recorded in 1595–1605; from Latin axis “a wild animal of India, perhaps the spotted deer” (Pliny)

Word History and Origins

Origin of axis¹

C18: from Latin: Indian wild animal, of uncertain identity

Origin of axis²

C14: from Latin: axletree, earth's axis; related to Greek axōn axis