A person or persons who have knowledge of, or see, a crime being committed. If identified, they can be compelled to give a statement under oath in a court room or to provide a deposition. In trials where the life of a witness or a witness’s family could be jeopardized if the witness provides testimony, they can be placed in a special protective care before, during, and after the trial. This is known as the Witness Security Program, where, upon completion of testifying in court, the witness and their family have the option to be provided with new identities and relocated.
To witness something does not always entail observing criminal activity. To bear witness can also mean having experiential knowledge of something. One can witness an act of kindness, a natural phenomenon, an accident, or a miracle. Similar to the witnessing a criminal act, these other acts of witness often entail an associated testimonial, where the witness shares their observations as evidence or proof their experience.