(agriculture) A farming practice in which the same land is used to grow different crops in successive seasons or years (when once the land would have been left fallow); used to prevent erosion and increase fertility.

(chemistry, of a compound) [α]_D, the angle of rotation of the plane of polarization of a ray of monochromatic light that passes through 10cm of the substance in solution at a concentration of 1 gram per millilitre

The rotary, rather than propulsive, motion produced by a propeller. / (mechanics) The rotation of the inner and outer parts of a bearing race.

The axis about which any body rotates. / The line joining the North Pole and South Pole about which the Earth rotates daily.

(physics) The kinetic energy of a rotating rigid body otherwise at rest.

(aviation, chiefly US) a rotating location light installed at an airport, allowing the type of airport to be determined by the color and speed of the rotation.

(forestry) The time allowed to elapse between successive occurrences of a stand of trees being logged. / Used other than figuratively or idiomatically: see rotation, time.

(mathematics) A method of finding a solution to a mathematical problem in Minkowski space from a solution to a related problem in Euclidean space by means of a transformation that substitutes an imaginary-number variable for a real-number variable.

Synonym of Norfolk crop rotation

plural of specific rotation