'To turn State's evidence' definitions:

Definition of 'To turn State's evidence'

From: GCIDE

Evidence \Ev"i*dence\, n. [F. ['e]vidence, L. Evidentia. See Evident.]
1. That which makes evident or manifest; that which furnishes, or tends to furnish, proof; any mode of proof; the ground of belief or judgement; as, the evidence of our senses; evidence of the truth or falsehood of a statement. [1913 Webster]
Faith is . . . the evidence of things not seen. --Heb. xi. 1. [1913 Webster]
O glorious trial of exceeding love Illustrious evidence, example high. --Milton. [1913 Webster]
2. One who bears witness. [R.] "Infamous and perjured evidences." --Sir W. Scott. [1913 Webster]
3. (Law) That which is legally submitted to competent tribunal, as a means of ascertaining the truth of any alleged matter of fact under investigation before it; means of making proof; -- the latter, strictly speaking, not being synonymous with evidence, but rather the effect of it. --Greenleaf. [1913 Webster]
Circumstantial evidence, Conclusive evidence, etc. See under Circumstantial, Conclusive, etc.
Crown's evidence, King's evidence, or Queen's evidence, evidence for the crown, in English courts; equivalent to state's evidence in American courts. [Eng.]
State's evidence, evidence for the government or the people. [U. S. ]
To turn King's evidence To turn Queen's evidence, or {To turn State's evidence}, to confess a crime and give evidence against one's accomplices.
Syn: Testimony; proof. See Testimony. [1913 Webster]