Game concept

Realm Capital

The game also links it as Realm Capitals, Capital, Capitals, Realm Capital's, Capital's.

From the game's encyclopedia

The Realm Capital is the Holding where a Ruler and their Court resides. This Holding has a Tax bonus, and is always inherited by the Primary Heir.

Occupying the Realm Capital of an enemy in a war gives a significant amount of War Score and sometimes lets you Imprison members of the enemy's family.

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.

Realm Capital is an entry of Crusader Kings III's in-game encyclopedia. The game explains it: "The Realm Capital is the Holding where a Ruler and their Court resides." The game also links it as Realm Capitals, Capital, Capitals, Realm Capital's and 1 more. 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.