Game concept
Home Court
The game also links it as Home Courts, Home Court's.
From the game's encyclopedia
A Ruler who is a Close Family Member of a Hostage and has sent them to a Warden as an assurance of peace or submission.
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.
Home Court is an entry of Crusader Kings III's in-game encyclopedia. The game explains it: "A Ruler who is a Close Family Member of a Hostage and has sent them to a Warden as an assurance of peace or submission." The game also links it as Home Courts and Home Court's. Patch 1.20.1.2, from game/common/game_concepts/05_bp2_game_concepts.txt and game/localization/english/game_concepts_l_english.yml.
Source: game/common/game_concepts/05_bp2_game_concepts.txt, game/localization/english/game_concepts_l_english.yml and the English localisation, Crusader Kings III 1.20.1.2.