## axis- In the mathematical sense, an axis is a line with respect to which a curve or figure is drawn, measured, rotated, etc. The word comes from the
Greek root
*aks*for a point of turning or rotation and seems to have first been used in English by Thomas Digges around 1570 in reference to the rotational axis of a right circular cone. In plane analytical geometry (and graphs) two axes, usually at right angles, are most commonly used. In three-dimensional geometry, three axes, usually at mutual right angles, are most common. Their point of intersection is the origin. - In astronomy and geography, an axis is an imaginary straight line through the center of celestial body, such as a planet or star, around which the body rotates. In mechanics, an axis runs longitudinally through the center of an axle or rotating shaft.
- In terms of flight, an axis is one of three lines of reference around which an aircraft or spacecraft can rotate. These lines are the longitudinal (front-to-back), horizontal, and vertical axes. Rotation along them is known as roll, pitch, and yaw, respectively.
## Related categories• ANALYTICAL GEOMETRY• GEOMETRY • GRAPHS AND GRAPH THEORY | |||||

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