18 U.S.C. § 2510 : US Code - Section 2510: Definitions

      As used in this chapter - 
        (1) "wire communication" means any aural transfer made in whole
      or in part through the use of facilities for the transmission of
      communications by the aid of wire, cable, or other like
      connection between the point of origin and the point of reception
      (including the use of such connection in a switching station)
      furnished or operated by any person engaged in providing or
      operating such facilities for the transmission of interstate or
      foreign communications or communications affecting interstate or
      foreign commerce;
        (2) "oral communication" means any oral communication uttered
      by a person exhibiting an expectation that such communication is
      not subject to interception under circumstances justifying such
      expectation, but such term does not include any electronic
      communication;
        (3) "State" means any State of the United States, the District
      of Columbia, the Commonwealth of Puerto Rico, and any territory
      or possession of the United States;
        (4) "intercept" means the aural or other acquisition of the
      contents of any wire, electronic, or oral communication through
      the use of any electronic, mechanical, or other device.(!1)

        (5) "electronic, mechanical, or other device" means any device
      or apparatus which can be used to intercept a wire, oral, or
      electronic communication other than - 
          (a) any telephone or telegraph instrument, equipment or
        facility, or any component thereof, (i) furnished to the
        subscriber or user by a provider of wire or electronic
        communication service in the ordinary course of its business
        and being used by the subscriber or user in the ordinary course
        of its business or furnished by such subscriber or user for
        connection to the facilities of such service and used in the
        ordinary course of its business; or (ii) being used by a
        provider of wire or electronic communication service in the
        ordinary course of its business, or by an investigative or law
        enforcement officer in the ordinary course of his duties;
          (b) a hearing aid or similar device being used to correct
        subnormal hearing to not better than normal;

        (6) "person" means any employee, or agent of the United States
      or any State or political subdivision thereof, and any
      individual, partnership, association, joint stock company, trust,
      or corporation;
        (7) "Investigative or law enforcement officer" means any
      officer of the United States or of a State or political
      subdivision thereof, who is empowered by law to conduct
      investigations of or to make arrests for offenses enumerated in
      this chapter, and any attorney authorized by law to prosecute or
      participate in the prosecution of such offenses;
        (8) "contents", when used with respect to any wire, oral, or
      electronic communication, includes any information concerning the
      substance, purport, or meaning of that communication;
        (9) "Judge of competent jurisdiction" means - 
          (a) a judge of a United States district court or a United
        States court of appeals; and
          (b) a judge of any court of general criminal jurisdiction of
        a State who is authorized by a statute of that State to enter
        orders authorizing interceptions of wire, oral, or electronic
        communications;

        (10) "communication common carrier" has the meaning given that
      term in section 3 of the Communications Act of 1934;
        (11) "aggrieved person" means a person who was a party to any
      intercepted wire, oral, or electronic communication or a person
      against whom the interception was directed;
        (12) "electronic communication" means any transfer of signs,
      signals, writing, images, sounds, data, or intelligence of any
      nature transmitted in whole or in part by a wire, radio,
      electromagnetic, photoelectronic or photooptical system that
      affects interstate or foreign commerce, but does not include - 
          (A) any wire or oral communication;
          (B) any communication made through a tone-only paging device;
          (C) any communication from a tracking device (as defined in
        section 3117 of this title); or
          (D) electronic funds transfer information stored by a
        financial institution in a communications system used for the
        electronic storage and transfer of funds;

        (13) "user" means any person or entity who - 
          (A) uses an electronic communication service; and
          (B) is duly authorized by the provider of such service to
        engage in such use;

        (14) "electronic communications system" means any wire, radio,
      electromagnetic, photooptical or photoelectronic facilities for
      the transmission of wire or electronic communications, and any
      computer facilities or related electronic equipment for the
      electronic storage of such communications;
        (15) "electronic communication service" means any service which
      provides to users thereof the ability to send or receive wire or
      electronic communications;
        (16) "readily accessible to the general public" means, with
      respect to a radio communication, that such communication is not -
       
          (A) scrambled or encrypted;
          (B) transmitted using modulation techniques whose essential
        parameters have been withheld from the public with the
        intention of preserving the privacy of such communication;
          (C) carried on a subcarrier or other signal subsidiary to a
        radio transmission;
          (D) transmitted over a communication system provided by a
        common carrier, unless the communication is a tone only paging
        system communication; or
          (E) transmitted on frequencies allocated under part 25,
        subpart D, E, or F of part 74, or part 94 of the Rules of the
        Federal Communications Commission, unless, in the case of a
        communication transmitted on a frequency allocated under part
        74 that is not exclusively allocated to broadcast auxiliary
        services, the communication is a two-way voice communication by
        radio;

        (17) "electronic storage" means - 
          (A) any temporary, intermediate storage of a wire or
        electronic communication incidental to the electronic
        transmission thereof; and
          (B) any storage of such communication by an electronic
        communication service for purposes of backup protection of such
        communication;

        (18) "aural transfer" means a transfer containing the human
      voice at any point between and including the point of origin and
      the point of reception;
        (19) "foreign intelligence information", for purposes of
      section 2517(6) of this title, means - 
          (A) information, whether or not concerning a United States
        person, that relates to the ability of the United States to
        protect against - 
            (i) actual or potential attack or other grave hostile acts
          of a foreign power or an agent of a foreign power;
            (ii) sabotage or international terrorism by a foreign power
          or an agent of a foreign power; or
            (iii) clandestine intelligence activities by an
          intelligence service or network of a foreign power or by an
          agent of a foreign power; or

          (B) information, whether or not concerning a United States
        person, with respect to a foreign power or foreign territory
        that relates to - 
            (i) the national defense or the security of the United
          States; or
            (ii) the conduct of the foreign affairs of the United
          States;

        (20) "protected computer" has the meaning set forth in section
      1030; and
        (21) "computer trespasser" - 
          (A) means a person who accesses a protected computer without
        authorization and thus has no reasonable expectation of privacy
        in any communication transmitted to, through, or from the
        protected computer; and
          (B) does not include a person known by the owner or operator
        of the protected computer to have an existing contractual
        relationship with the owner or operator of the protected
        computer for access to all or part of the protected computer.