In Drupal parlance, distributions refer to variations of Drupal that include Drupal core in its entirety and other items such as themes, modules, libraries (for front-end assets), and installation profiles. Distributions can be full-featured, meaning they are comprehensive solutions for use in specialized cases, or they can act as quick-start tools that help developers and site builders get going quickly.1
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Some commonly used distributions in Drupal include Conference Organizing Distribution (COD) for conference web sites; Open Social for social communities, intranets, and networks; ...