Main Entry: gy·ro·scope

Pronunciation: \ˈjī-rə-ˌskōp, British also ˈgī-\

Function: noun

Etymology: French

Date: 1856

: a wheel or disk mounted to spin rapidly about an axis and also free to rotate about one or both of two axes perpendicular to each other and to the axis of spin so that a rotation of one of the two mutually perpendicular axes results from application of torque to the other when the wheel is spinning and so that the entire apparatus offers considerable opposition depending on the angular momentum to any torque that would change the direction of the axis of spin

— gy·ro·scop·ic \ˌjī-rə-ˈskä-pik\ adjective

— gy·ro·scop·i·cal·ly \-pi-k(ə-)lē\ adverb

[gyroscope illustration]