(A) with respect to an executive agency means any equipment or interconnected system or subsystem of equipment, used in the automatic acquisition, storage, analysis, evaluation, manipulation, management, movement, control, display, switching, interchange, transmission, or reception of data or information by the executive agency, if the equipment is used by the executive agency directly or is used by a contractor under a contract with the executive agency that requires the use— (i) of that equipment; or (ii) of that equipment to a significant extent in the performance of a service or the furnishing of a product; (B) includes computers, ancillary equipment (including imaging peripherals, input, output, and storage devices necessary for security and surveillance), peripheral equipment designed to be controlled by the central processing unit of a computer, software, firmware and similar procedures, services (including support services), and related resources; but (C) does not include any equipment acquired by a federal contractor incidental to a federal contract.
Sources:
NIST SP 800-12 Rev. 1 under Information Technology from 40 U.S.C., Sec. 11101

  The term 'information technology', with respect to an executive agency means any equipment or interconnected system or subsystem of equipment, that is used in the automatic acquisition, storage, manipulation, management, movement, control, display, switching, interchange, transmission, or reception of data or information by the executive agency. For purposes of the preceding sentence, equipment is used by an executive agency if the equipment is used by the executive agency directly or is used by a contractor under a contract with the executive agency which (i) requires the use of such equipment, or (ii) requires the use, to a significant extent, of such equipment in the performance of a service or the furnishing of a product. The term ''information technology'' includes computers, ancillary equipment, software, firmware and similar procedures, services (including support services), and related resources. The term ''information technology'' does not include any equipment that is acquired by a Federal contractor incidental to a Federal contract.
Sources:
NIST SP 800-59 under Information Technology from 40 U.S.C., Sec. 11101 (6)

  Any services, equipment, or interconnected system(s) or subsystem(s) of equipment, that are used in the automatic acquisition, storage, analysis, evaluation, manipulation, management, movement, control, display, switching, interchange, transmission, or reception of data or information by the agency. For purposes of this definition, such services or equipment if used by the agency directly or is used by a contractor under a contract with the agency that requires its use; or to a significant extent, its use in the performance of a service or the furnishing of a product. Information technology includes computers, ancillary equipment (including imaging peripherals, input, output, and storage devices necessary for security and surveillance), peripheral equipment designed to be controlled by the central processing unit of a computer, software, firmware and similar procedures, services (including cloud computing and help-desk services or other professional services which support any point of the life cycle of the equipment or service), and related resources. Information technology does not include any equipment that is acquired by a contractor incidental to a contract which does not require its use.
Sources:
NIST SP 800-128 under information technology
NIST SP 800-160 Vol. 2 Rev. 1 under information technology from OMB Circular A-130 (2016)
NIST SP 800-172 under information technology from OMB Circular A-130 (2016)
NIST SP 800-172A under information technology from OMB Circular A-130 (2016)
NIST SP 800-37 Rev. 2 under information technology from OMB Circular A-130 (2016)
NIST SP 800-53 Rev. 5 under information technology from 40 U.S.C., Sec. 11101
NIST SP 800-53A Rev. 5 under information technology from 40 U.S.C., Sec. 11101
NIST SP 800-171 Rev. 2 under information technology from OMB Circular A-130 (2016)

  Any equipment or interconnected system or subsystem of equipment that is used in the automatic acquisition, storage, manipulation, management, movement, control, display, switching, interchange, transmission, or reception of data or information by the executive agency. For purposes of the preceding sentence, equipment is used by an executive agency if the equipment is used by the executive agency directly or is used by a contractor under a contract with the executive agency which: (i) requires the use of such equipment; or (ii) requires the use, to a significant extent, of such equipment in the performance of a service or the furnishing of a product. The term information technology includes computers, ancillary equipment, software, firmware, and similar procedures, services (including support services), and related resources.
Sources:
CNSSI 4009-2015 under information technology from 40 U.S.C., Sec. 11101 - adapted, 40 U.S.C., Sec. 1401 - adapted
NIST SP 800-128 under Information Technology from 40 U.S.C., Sec. 1401
NIST SP 800-137 under Information Technology from 40 U.S.C., Sec. 1401
NIST SP 800-18 Rev. 1 under Information Technology from 40 U.S.C., Sec. 1401
NIST SP 800-30 Rev. 1 under Information Technology from 40 U.S.C., Sec. 1401
NIST SP 800-39 under Information Technology from 40 U.S.C., Sec. 1401
NIST SP 800-60 Vol. 1 Rev. 1 under Information Technology from 40 U.S.C., Sec. 1401
NIST SP 800-60 Vol. 2 Rev. 1 under Information Technology from 40 U.S.C., Sec. 1401
NISTIR 8170 under Information Technology from 40 U.S.C., Sec. 1401

  Any equipment or interconnected system or subsystem of equipment that is used in the automatic acquisition, storage, manipulation, management, movement, control, display, switching, interchange, transmission, or reception of data or information by the executive agency.
Sources:
NIST SP 1800-10B under Information Technology from FIPS 200 - Adapted

  The art and applied sciences that deal with data and information. Examples are capture, representation, processing, security, transfer, interchange, presentation, management, organization, storage, and retrieval of data and information.
Sources:
NISTIR 8074 Vol. 2 under Information Technology from ANSDIT