Definition of material witness in English:

material witness

noun

US
Law
  • A witness whose evidence is likely to be sufficiently important to influence the outcome of a trial.

    • ‘However at that time, the police, who were the only material witnesses in the case, were still in Castries.’
    • ‘Elements of both crimes are clearly demonstrated in the declarations of the material witnesses.’
    • ‘A federal district court judge says the Justice Department may not jail material witnesses indefinitely.’
    • ‘Justice officials insist that more than half of the detained material witnesses have ended up in criminal prosecutions.’
    • ‘A person who was eyewitness to an event can be a material witness.’