Game concept
Interaction
The game also links it as Character Interaction, Interactions, Interacting.
From the game's encyclopedia
Actions taken by one character towards another. They can have a wide range of purposes and effects.
Some interactions require the target character's approval, while some can be performed without it.
Usually they are accessed by right-clicking on a character to access the Interaction Menu for the target character, but sometimes they are available through special interfaces.
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.
Interaction is an entry of Crusader Kings III's in-game encyclopedia. The game explains it: "Actions taken by one character towards another." It covers Offer Vassalization, Demand Payment, Buy Claim, Buy Artifact Claim, Dismiss Hook Interaction and 13 more. The game also links it as Character Interaction, Interactions and Interacting. 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.