Game concept
Title Law
The game also links it as Title Laws.
From the game's encyclopedia
Titles can be given a Title-Specific Law that is specific to that Title. This Law will dictate different rules for succession than other titles held by the same character.
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.
Title Law is an entry of Crusader Kings III's in-game encyclopedia. The game explains it: "Titles can be given a Title-Specific Law that is specific to that Title." It is part of Law. The game also links it as Title Laws. Patch 1.20.1.2, from game/common/game_concepts/00_game_concepts.txt and game/localization/english/game_concepts_l_english.yml.
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.