1. An update to an operating system, application, or other software issued specifically to correct particular problems with the software.

Source: The State and Local Election Cybersecurity Playbook, Defending Digital Democracy Project, Harvard Kennedy School Belfer Center for Science and International Affairs,

2. A patch to source code is a change (or commit). Within the context we are discussing them, a patch closes a vulnerability in software.

Source: Open Source Voting in San Francisco, City and County of San Francisco,

3. Software which replaces the faulty part of a programme with a faultfree version. Patches are used to eliminate security holes (vulnerabilities).

Source: Information Assurance Situation in Switzerland and Internationally, Reporting and Analysis Centre for Information Assurance MELANI,

4. A software component that, when installed, directly modifies files or device settings related to a different software component without changing the version number or release details for the related software component.

Source: U.S. Cyberspace Solarium Commission, March 2020,