A fact that would be important to a reasonable person in deciding whether to engage or not to engage in a particular transaction; an important fact as distinguished from some unimportant or trivial detail.
The word "material" means that the subject matter of the statement [or concealment] related to a fact or circumstance which would be important to the decision to be made as distinguished from an insignificant, trivial or unimportant detail. (e.g. re: insurance fraud
To be material, an assertion [or concealment] must relate to a fact or circumstance that would affect the liability of an insurer (if made during an investigation of the loss), or would affect the decision to issue the policy, or the amount of coverage or the premium (if made in the application for the policy).
A material fact is one which might affect the outcome of the case under governing law. Anderson v. Liberty Lobby, Inc., 477 U.S. 242, 248 (1986). To preclude summary judgment, the dispute about a material fact must also be "genuine," such that a reasonable jury could find in favor of the non-moving party. Id.
That which is important; that which is not merely of form but of substance. When a bill for discovery has been filed, for example, the defendant must answer every material fact which is charged in the bill, and the test in these cases seems to be that when, if the defendant should answer in the affirmative, his answer would be of use to the plaintiff, the answer would be material, and it must be made. In order to convict a witness of a perjury, it is requisite to prove that the matter he swore to was material to the question then depending.