18 Pa. C.S. § 4951
The following words and phrases when used in this subchapter shall have, unless the context clearly indicates otherwise, the meanings given to them in this section:
"Victim." Any person against whom any crime as defined under the laws of this State or of any other state or of the United States is being or has been perpetrated or attempted.
"Witness." Any person having knowledge of the existence or nonexistence of facts or information relating to any crime, including but not limited to those who have reported facts or information to any law enforcement officer, prosecuting official, attorney representing a criminal defendant or judge, those who have been served with a subpoena issued under the authority of this State or any other state or of the United States, and those who have given written or oral testimony in any criminal matter; or who would be believed by any reasonable person to be an individual described in this definition.
18 Pa.C.S. § 4951