the act of rotating as if on an axis; "the rotation of the dancer kept time with the music"
a planned recurrent sequence (of crops or personnel etc.); "crop rotation makes a balanced demand on the fertility of the soil"; "the manager had only four starting pitchers in his rotation"
a single complete turn (axial or orbital); "the plane made three rotations before it crashed"; "the revolution of the earth about the sun takes one year"
(mathematics) a transformation in which the coordinate axes are rotated by a fixed angle about the origin
having the function of uniting a group of similar things; "the Democratic Party is an umbrella for many liberal groups"; "under the umbrella of capitalism"
a formation of military planes maintained over ground operations or targets; "an air umbrella over England"
a lightweight handheld collapsible canopy
covering or applying simultaneously to a number of similar items or elements or groups; "an umbrella organization"; "umbrella insurance coverage"