Operating system
A collection of programs that controls the hardware of a computer system and provides utilities and services to application software that is installed on the device. Operating systems use complex release version numbers to indicate which version is installed and require frequent patches or updates to maintain security and functionality. Managing the software revisions in an election office requires careful coordination of updates to the operating system as well as to the application software.
Source: Information Technology Terminology, U.S. Election Assistance Commission, https://www.eac.gov/documents/2017/09/21/information-technology-terminology-security