1. A server is a collection of computer programs, hosted on a computer that provides services to other computers, via some connection – usually a network. Voting systems use special-purpose servers to create closed networks for uploading and downloading information from voting system media (memory cards). These servers also contain the tabulation software.
Source: Information Technology Terminology, U.S. Election Assistance Commission, https://www.eac.gov/documents/2017/09/21/information-technology-terminology-security
2. A machine that provides services (for instance a web server, e-mail server, proxy server, file server, or print server) to other machines. In general, all machines on the Internet fall into two categories: clients and servers. Where the available intelligence permits, specify the type of server involved (e.g., an e-mail server).
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