The establishment of a fact by the use of evidence. Anything that can make a person believe that a fact or proposition is true or false. It is distinguishable from evidence in that proof is a broad term comprehending everything that may be adduced at a trial, whereas evidence is a narrow term describing certain types of proof that can be admitted at trial.
The phrase burden of proof includes two distinct concepts, the burden of persuasion and the burden of going forward. The burden of persuasion is the duty of a party to convince the trier of fact of all the elements of a cause of action. The burden of going forward refers to the need of a party to refute evidence introduced at trial that damages or discredits his or her position in the action. The burden of persuasion remains with the plaintiff or prosecutor throughout the action, whereas the burden of going forward can shift between the parties during the trial.
In a civil action, the requisite degree of proof is a preponderance of the evidence.The plaintiff must show that more probably than not the defendant violated his or her rights. In a criminal action, the prosecutor has the burden of establishing guilt beyond a reasonable doubt.
Hence proof adj. of tested strength XVI; prob. from ellipsis of of in † armour of proof.
See also burden of proof.