turn king's evidence

: to cause to move around an axis or a center : make rotate or revolve

: to cause to move around so as to effect a desired end (as of locking, opening, or shutting)

: to affect or alter the functioning of (something, such as a mechanical device) or the level of (something, such as sound) by such movement

: the action or an act of turning about a center or axis : revolution, rotation

: any of various rotating or pivoting movements in dancing or gymnastics

: the action or an act of giving or taking a different direction : change of course or posture : such as

: a male monarch of a major territorial unit

: a paramount chief

: god, christ

: an outward sign : indication

: something that furnishes proof : testimony

: one who bears witness

: to offer evidence of : prove, evince