axis
1 Americannoun
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axes
plural
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the line about which a rotating body, such as the earth, turns.
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Mathematics.
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a central line that bisects a two-dimensional body or figure.
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a line about which a three-dimensional body or figure is symmetrical.
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Anatomy.
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a central or principal structure, about which something turns or is arranged.
the skeletal axis.
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the second cervical vertebra.
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Botany. the longitudinal support on which organs or parts are arranged; the stem and root; the central line of any body.
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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.
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Crystallography. crystallographic axis.
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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.
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Fine Arts. an imaginary line, in a given formal structure, about which a form, area, or plane is organized.
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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.
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the Axis, (in World War II) Germany, Italy, and Japan, often with Bulgaria, Hungary, and Romania.
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a principal line of development, movement, direction, etc.
noun
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axises
plural
noun
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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
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one of two or three reference lines used in coordinate geometry to locate a point in a plane or in space
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anatomy the second cervical vertebra Compare atlas
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botany the main central part of a plant, typically consisting of the stem and root, from which secondary branches and other parts develop
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an alliance between a number of states to coordinate their foreign policy
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Also called: principal axis. optics the line of symmetry of an optical system, such as the line passing through the centre of a lens
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geology an imaginary line along the crest of an anticline or the trough of a syncline
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crystallog one of three lines passing through the centre of a crystal and used to characterize its symmetry
noun
noun
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axes
plural
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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.
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Mathematics
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A line, ray, or line segment with respect to which a figure or object is symmetrical.
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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.
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Anatomy The second cervical vertebra, which serves as a pivot for the head.
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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.
Usage
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?
Discover More
The axis of the Earth is an imaginary line drawn through the North Pole and the South Pole.
Other Word Forms
Derived Forms
Inflected Forms
Nouns
Etymology
Origin of axis1
First recorded in 1350–1400; Middle English; from Latin axis “an axletree, axle, axis”; see origin at axi-
Origin of axis2
First recorded in 1595–1605; from Latin axis “a wild animal of India, perhaps the spotted deer” (Pliny)
Explanation
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.
Vocabulary lists containing axis
Over The Moon: Planetary Vocabulary
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March Vocabulary Words
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Weather and Climate - Introductory
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Example Sentences
Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.
See Examples For:
In alternating, time-traveling, distinctly voiced chapters, the four quirky members of a modern Midwestern family spin on the tilted axis of Barbara, their dementia-impaired matriarch.
From Los Angeles Times ● Sep. 8, 2026
The Earth all but shifted on its axis following this, due to the breathtakingly bonkers discourse that followed the incident.
From Salon ● Sep. 8, 2026
As the main axis is there, I expect them to get very close to winning it again.
From BBC ● Sep. 7, 2026
The Sun's gravitational pull on Mars changes over the course of the planet's seasons because Mars travels along a slightly elliptical orbit and rotates on a tilted axis.
From Science Daily ● Aug. 30, 2026
Jasmine felt the world had spun off its axis.
From "The 57 Bus" by Dashka Slater
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Earlier, a number of specimens, including parts of the early dinosaur Thecodontosaurus, were destroyed in Bristol after an Axis raid in 1940.
From Science Daily ● Aug. 7, 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
Bajaj Finance fell 5.4% and Axis Bank lost 3.7%.
From The Wall Street Journal ● Mar. 19, 2026
By the end of September 1940, Hungary and Romania had also joined the Axis nations—both countries shared borders with the Soviet state of Ukraine, and hoped Germany would help protect them from the Soviet Union.
From "A Thousand Sisters" by Elizabeth Wein
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But they were pushed back this week, and the government launched a counter-offensive into Tigrayan territory along three axes towards Mekelle, according to the Critical Threats Project, part of the American Enterprise Institute think tank.
From Barron's ● Oct. 3, 2026
It is his Excalibur, his Andúril, the vaunted weapon only he can string and use to hit a bullseye through a row of twelve crossed axes.
From Salon ● Aug. 2, 2026
It bears heavy signs of use and was made by Fuhrer Frères of Gstaad, the same Swiss firm that supplied fifteen axes to the 1924 Everest expedition.
From BBC ● Jul. 12, 2026
"Meaning, as they spin around on their axes and orbit around their parents, those rates/frequencies match, leading to the phenomena like us only seeing one side of our moon."
From Science Daily ● Jul. 9, 2026
Once, yes, but axes had long since cleared the trees away.
From "A Dance with Dragons" by George R. R. Martin
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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.