Admissible evidence, in a court of law, is any testimonial, documentary, or tangible evidence that may be introduced to a factfinder - usually a judge or jury in order to establish or a bolster a point put forth by a party to the proceeding. In order for evidence to be admissible, it must be relevant, without being prejudicial, and it have some indicia of reliability. A court is an official, public forum which a public power establishes by lawful authority to adjudicate disputes, and to dispense civil, labour, administrative and criminal justice under the law. ... Law (a loanword from Old Norse lag), in politics and jurisprudence, is a set of rules or norms of conduct which mandate, proscribe or permit specified relationships among people and organizations, provide methods for ensuring the impartial treatment of such people, and provide punishments for those who do not follow... The law of evidence governs the use of testimony (eg. ... A judge or justice is an appointed or elected official who presides over a court. ... This article is confusing for some readers, and needs to be edited for clarity. ...

For evidence to be relevant, it must tend to prove or disprove some fact that is at issue in the proceeding. However, if the utility of this evidence is outweighed by its tendancy to cause the factfinder to disaprove of the party it is introduced against for some unrelated reason, it will not be admissible. Furthermore, certain public policy considerations bar the admission of otherwise relevant evidence.

For evidence to be reliable enough to be admitted, the party proffering the evidence must be able to show that the source of the evidence makes it so. If the evidence is in the form of witness testimony, the party introducing the evidence must lay the groundwork for the credibility of the witness, and his knowledge of the things to which he attests. Hearsay is generally barred for its lack of reliability. If the evidence is documentary, the party proffering the evidence must be able to that it is authentic, and must be able to demonstrate the chain of custody from the original author to the present holder. This article is about witnesses in law courts. ... Hearsay in its most general and oldest meaning is a term used in the law of evidence to describe an out of court statement offered to establish the facts asserted in that statement. ... The chain of custody is a concept in jurisprudence which applies to the handling of evidence and its integrity. ...