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axis Syllabification: ax·is
Pronunciation: /ˈaksəs/

Definition of axis in English:

noun (plural axesˈaksēz)

1An imaginary line about which a body rotates: the earth revolves on its axis once every 24 hours
More example sentences
  • The earth rotates once on its axis each day, or 360 degrees every 24 hours, or 15 degrees every hour.
  • To say that the Earth rotates on its axis once per day and completes one orbit of the Sun each year is to encapsulate but also to simplify the situation.
  • The sphere rotates around its axis once each 24 hours.
1.1 Geometry An imaginary straight line passing through the center of a symmetrical solid, and about which a plane figure can be conceived as rotating to generate the solid.
Example sentences
  • If a plane figure is rotated about an axis in its plane then the volume of the solid body formed is equal to the product of the area with the distance travelled by the centre of gravity.
  • He examined the three dimensional figures obtained by rotating a regular polygon about an axis of symmetry.
  • Many eighteenth-century manuals on gauging treated barrels as solids generated by rotating conic sections about their axes.
1.2An imaginary line that divides something into equal or roughly equal halves, especially in the direction of its greatest length.
Example sentences
  • The horizontal axis divides the short and long arms into approximately a proximal one-third and distal two-thirds portions.
  • The width of a molecule at a given point along the contour length is the diameter of the horizontal axis of the elliptical cross section at that point.
  • Koch analyses that in Shah Jahan era, painting third dimension reality is flattened and arranged around a central axis that divides the picture into two equal parts.
2 Mathematics A fixed reference line for the measurement of coordinates: the variable that is thought of as a cause is placed on the horizontal axis, and the variable that is thought of as an effect on the vertical axis
More example sentences
  • They orient along the x, y, and z axes of a Cartesian coordinate system.
  • As the abscissas of points 1 and 18 were used to define a reference axis, only their ordinates were used.
  • The abscissa and ordinate axes show the number of protein interactions for the first and second protein member of each pair.
3A straight central part in a structure to which other parts are connected.
Example sentences
  • A shaft parallel to the transmission-engine axis connects the transfer casing to the angle drive powering the front wheels.
  • The new masterplan attempts to alleviate this by organising a series of public spaces about an axis connecting Lancer Barracks and St John's Church.
  • A pedestrian axis will connect Alumni Green to the new Fairfax atrium.
3.1 Botany The central column of an inflorescence or other growth.
Example sentences
  • The sympodia are arranged more or less parallel to the stem axis and follow the phyllotactic spirals of the leaves.
  • Each module of a sympodium consists of an axis bearing two bracts and terminating in a flower.
  • In addition, the stems (including the axis of the inflorescence) serve as temporary storage sites.
3.2 Zoology The skull and backbone of a vertebrate animal.
Example sentences
  • This is the architecture that supports and is supported by the vertebrate axis, namely the notochord or vertebral column.
  • The caudal fin represents the distal region of the vertebrate axis and is the region of the body where fluid accelerated anteriorly is shed into the surrounding medium.
  • Without functional analyses of axial ligaments, the basis for flexural stiffness in any particular vertebrate axis is wanting.
4 Anatomy The second cervical vertebra, below the atlas at the top of the backbone.
Example sentences
  • The muscle's origin may not ascend above the axis or descend below the third thoracic vertebra.
  • The axis may be fused with either the atlas or with the third vertebra.
5An agreement or alliance between two or more countries that forms a center for an eventual larger grouping of nations: the Anglo-American axis
More example sentences
  • Deals and manoeuvres are still being made, and there has been no final determination of international axes and power blocs.
  • This most recent episode sheds new light on the political axis that underlies the Democratic Party campaign.
  • Most of all, the assertion of the Anglo-Iberian alliance is designed as a counterweight to the Franco-German axis.
5.1 (the Axis) The alliance of Germany and Italy formed before and during World War II, later extended to include Japan and other countries: [as modifier]: the Axis Powers
More example sentences
  • Its name originated as a cover term for the countries which fought against the Axis in the Second World War.
  • Unlike the Grand Alliance, the Axis coalition formed by the pact had no agreed strategy for fighting the war.
  • In North Africa, it represented the whole Free World against the Axis powers - Germany and Italy.


Late Middle English: from Latin, 'axle, pivot'.

  • In Latin axis means ‘axle’ or ‘pivot’. That is really what an axis is—an imaginary line through a body, around which it rotates, rather like an invisible axle. In the Second World War the Axis was the alliance of Germany and Italy, later also including Japan and other countries, which opposed the Allies. The connection with an axis was the idea of the relations between countries forming a ‘pivot’ around which they revolved. See also evil.

Words that rhyme with axis

anaphylaxis, praxis, taxis

Definition of axis in:

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