Game concept
Liege
The game also links it as Lieges, Liege's.
From the game's encyclopedia
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.
Liege is an entry of Crusader Kings III's in-game encyclopedia. The game explains it: "A Liege is a Ruler with at least one Vassal." It is part of Ruler. It covers Rightful Liege and Top Liege. The game also links it as Lieges and Liege's. Patch 1.20.1.2, from game/common/game_concepts/00_game_concepts.txt and game/localization/english/game_concepts_l_english.yml.
for a guide, post or blog
Source: game/common/game_concepts/00_game_concepts.txt, game/localization/english/game_concepts_l_english.yml and the English localisation, Crusader Kings III 1.20.1.2.