Bra·dy ma·te·ri·al /'brā-dē-/ n [from Brady v. Maryland, 373 U.S. 83 (1963), in which the Supreme Court ruled that suppression by the prosecution of evidence favorable to a defendant who has requested it violates due process]: evidence known to the prosecution that is favorable to a defendant's case and material to the issue of guilt or to punishment and that the prosecution is obligated to disclose to the defense: exculpatory evidence known to the prosecution that must be disclosed
Merriam-Webster’s Dictionary of Law. Merriam-Webster. 1996.