As used in this subdivision, the following words and phrases shall have the following meanings, respectively, unless the context clearly indicates otherwise:
(1) WITNESS. A person whose testimony is desired in any proceeding or investigation by a grand jury or in a criminal action, prosecution or proceeding.
(2) STATE. Any state or territory of the United States and the District of Columbia.
(3) SUMMONS. A subpoena, order or other notice requiring the appearance of a witness.