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, https://www.belfercenter.org/sites/default/files/files/publication/StateLocalPlaybook%201.1.pdf
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, http://civilgrandjury.sfgov.org/2017_2018/2017-18_SFCGJ_Final_Report_Open_Source_Voting_in_San_Francisco.pdf
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, https://www.newsd.admin.ch/newsd/message/attachments/11945.pdf
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, https://subscriber.politicopro.com/f/?id=00000170-c638-d8f7-a7f1-f63b33510000