Game concept
Dissolution Faction
The game also links it as Dissolution Factions, Dissolved.
From the game's encyclopedia
The Dissolution Faction seeks to destroy the Realm of their Liege. If they are successful, all the vassals in the realm become Independent, and their liege loses their Primary Title.
The game's text for patch 1.20.1.2. Words in blue are entries of the encyclopedia: hover one to read it, as in the game.
Dissolution Faction is an entry of Crusader Kings III's in-game encyclopedia. The game explains it: "The Dissolution Faction seeks to destroy the Realm of their Liege." It is part of Faction. The game also links it as Dissolution Factions and Dissolved. Patch 1.20.1.2, from game/common/game_concepts/03_fp2_game_concepts.txt and game/localization/english/game_concepts_l_english.yml.
Source: game/common/game_concepts/03_fp2_game_concepts.txt, game/localization/english/game_concepts_l_english.yml and the English localisation, Crusader Kings III 1.20.1.2.