Game concept
Holding
The game also links it as Holdings.
From the game's encyclopedia
A Holding is the central settlement of a Barony or County Capital.
It provides Taxes and Levies to its Holder, depending on its Holding Type. The collection of Holdings personally owned by a Ruler is called a Domain.
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.
Holding is an entry of Crusader Kings III's in-game encyclopedia. The game explains it: "A Holding is the central settlement of a Barony or County Capital." It covers Holding Type. The game also links it as Holdings. 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.