A material fact is a fact that a reasonable person would recognize as relevant to a decision to be made, as distinguished from an insignificant, trivial, or unimportant detail.
In other words, it is a fact, the suppression of which would reasonably result in a different decision.
[1][2] Falsification of a material fact that would cause a party to a contract to refrain from entering into the contract may be grounds for rescission.
For example, misrepresentation of a material fact on an application for insurance may give an insurance company grounds to rescind an insurance policy.
[3]