Materiality is a legal

Law

Law is a system of rules and guidelines which are enforced through social institutions to govern behavior, wherever possible. It shapes politics, economics and society in numerous ways and serves as a social mediator of relations between people. Contract law regulates everything from buying a bus...

 term which can have different meanings, depending on context. When speaking of facts, the term generally means a fact which is "significant to the issue or matter at hand".
An item of evidence

Evidence (law)

The law of evidence encompasses the rules and legal principles that govern the proof of facts in a legal proceeding. These rules determine what evidence can be considered by the trier of fact in reaching its decision and, sometimes, the weight that may be given to that evidence...

 is said to be material if it has some logical connection to a fact of consequence to the outcome of a case

Legal case

A legal case is a dispute between opposing parties resolved by a court, or by some equivalent legal process. A legal case may be either civil or criminal...

. Materiality, along with probative

Probative

Relevance, in the common law of evidence, is the tendency of a given item of evidence to prove or disprove one of the legal elements of the case, or to have probative value to make one of the elements of the case likelier or not. Probative is a term used in law to signify "tending to prove."...

 value, is one of the two characteristics which makes a given item of evidence relevant

Relevance (law)

Relevance, in the common law of evidence, is the tendency of a given item of evidence to prove or disprove one of the legal elements of the case, or to have probative value to make one of the elements of the case likelier or not. Probative is a term used in law to signify "tending to prove."...

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