the line about which a rotating body, such as the earth, turns.
Mathematics.
a central line that bisects a two-dimensional body or figure.
a line about which a three-dimensional body or figure is symmetrical.
Anatomy.
a central or principal structure, about which something turns or is arranged.
the skeletal axis.
the second cervical vertebra.
Botany. the longitudinal support on which organs or parts are arranged; the stem and root; the central line of any body.
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.
Crystallography. crystallographic 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.
Fine Arts. an imaginary line, in a given formal structure, about which a form, area, or plane is organized.
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.
the Axis, (in World War II) Germany, Italy, and Japan, often with Bulgaria, Hungary, and Romania.
a principal line of development, movement, direction, etc.
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
one of two or three reference lines used in coordinate geometry to locate a point in a plane or in space
anatomy the second cervical vertebra Compare atlas
botany the main central part of a plant, typically consisting of the stem and root, from which secondary branches and other parts develop
an alliance between a number of states to coordinate their foreign policy
Also called: principal axis. optics the line of symmetry of an optical system, such as the line passing through the centre of a lens
geology an imaginary line along the crest of an anticline or the trough of a syncline
crystallog one of three lines passing through the centre of a crystal and used to characterize its symmetry
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.
Plural word for axis The plural form of axis is axes, pronounced [ ak-seez ]. The plurals of several other singular words that end in -sis are also formed in the same way, including hypothesis/hypotheses, analysis/analyses, and crisis/crises. A similar change is made when pluralizing appendix as appendices. Irregular plurals that are formed like axes derive directly from their original pluralization in Latin and Greek. Be careful: axes is also the plural of ax (and its alternate spelling axe), but in this case it’s pronounced [ ak-siz ]. Do you know: What is the plural of matrix?
The axis of the Earth is an imaginary line drawn through the North Pole and the South Pole.
First recorded in 1350–1400; Middle English; from Latin axis “an axletree, axle, axis”; see origin at axi-
First recorded in 1595–1605; from Latin axis “a wild animal of India, perhaps the spotted deer” (Pliny)
An axis is a straight line, sometimes seen, sometimes not, that is important in mathematics, art, science and our survival. The most famous axis is the one the earth spins around, giving us the 24-hour day. In graphs, one side is usually the "X axis" and the other the "Y axis." Axis lines are also the lines that run through spheres, like our earth, around which those spheres rotate. In a totally different area, axis is used to describe countries in an alliance. During World War II, Germany, Japan, and Italy were known as the Axis Powers.
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Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.
It’s about the fact that the Lotus’s polar axis runs exactly through the driver’s inboard hip, so that the machine rotates around them and not some invisible pivot point, just off-center.
From The Wall Street Journal ● Jul. 25, 2026
The emergent Turkey-led axis, which may be trying to draw in Saudi Arabia, is another.
From The Wall Street Journal ● Jul. 12, 2026
"Semiconductors, physical AI, and AI data centres are the triple axis for a great leap forward."
From BBC ● Jun. 29, 2026
The reflecting pool sits along the axis between the Lincoln Memorial and the Washington Monument and is among the most photographed sites in Washington, amplifying attention on any visible changes.
From Salon ● Jun. 19, 2026
Every segment of an embryo can be defined on an axis that stretches from head to tail.
From "The Gene" by Siddhartha Mukherjee
The campaigns to capture that oil and defeat the Red Army, as well as the Axis forces’ second front in North Africa, are the subjects of “1942: Hitler’s Gamble for Victory.”
From The Wall Street Journal ● Jun. 23, 2026
Such a message would have particular importance for Hezbollah, Iraqi militias and other members of Iran's regional network known as the "Axis of Resistance".
From BBC ● Jun. 8, 2026
Army colonel Lee Shaw, her team’s father figure, in the monster realm they call Axis Mundi.
From Salon ● Mar. 20, 2026
About the author: Omar Al-Ghusbi is a senior analyst at C4ADS and co-author of the Airborne Axis: Inside the Deal That Brought Iranian Drone Production to Russia External link report.
From Barron's ● Mar. 17, 2026
In other words, anyone who was from a country that was part of the Axis, Germany's allies.
From Nazi Saboteurs by Samantha Seiple
It ends a valuable deferred compensation program, axes health benefits and changes commissions on several types of policy, according to agents and company documents reviewed by the Journal.
From The Wall Street Journal ● Jun. 17, 2026
One location stood out due to the discovery of about 80 grooved stone axes, which were used to break down and process ore.
From Science Daily ● Apr. 29, 2026
Unlike thieves who carry weapons into museums or use axes to smash-and-grab, art-world scammers rarely get violent—so their prison sentences often get cut short.
From The Wall Street Journal ● Jan. 11, 2026
The towering ambition of the men remaking the landscape with saws and axes, and the men, like Grainier, who were somehow pulled through that current.
From Los Angeles Times ● Jan. 5, 2026
This was before the UN brought us tools, so we had no shovels, axes, or spades.
From "Lost Boy, Lost Girl" by John Bul Dau
Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023
Idioms from The American Heritage® Idioms Dictionary copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.
