1. An information system comprising a collection of interconnected computers or devices.
Source: Cyber Threats to Elections – A Lexicon, Cyber Threat Intelligence Integration Center & Office of the Director of National Intelligence, https://www.dni.gov/files/CTIIC/documents/CTIIC_2018_Lexicon_without_banner_small_file_for_Post.pdf
2. An Information system implemented with a collection of interconnected components, which may include routers, hubs, cabling, telecommunications controllers, key distribution centers, and technical control devices. (NIST Glossary of Information Security Terms – NIST IR 7298 – Revision 2).
Source: NSTAC Report to the President on a Cybersecurity Moonshot, National Security Telecommunications Advisory Committee (NSTAC), https://www.dhs.gov/sites/default/files/publications/NSTAC_CyberMoonshotReport_508c.pdf