Legal Definitions - state secret

A state secret is information that is possessed by the government and is of a military or diplomatic nature. If this information is revealed, it could be a threat to the national defense or diplomatic interests of the United States. The disclosure of state secrets would be contrary to the public interest. State secrets are privileged from disclosure by a witness in an ordinary judicial proceeding. This means that a witness cannot be forced to reveal state secrets in court.

For example, if a government official has information about a secret military operation that could harm national security if revealed, they cannot be forced to disclose that information in court. This is because the disclosure of state secrets could be a threat to national defense.