- 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
- 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,
AND GRAPH THEORY