Habitable World
Habitable World (exploration) in the Stellaris encyclopedia: Habitable Worlds are bodies that can support Pops and be developed into Colonies. This includes both naturally occurring Planets, artificially constructed Habitats, and Ring Worlds.
Habitable World in the game's words
The encyclopedia entry as the game shows it in its tooltips; underlined words open their own entry or page here.
Habitable Worlds are bodies that can support 
Pops and be developed into 
Colonies. This includes both naturally occurring 
Planets, artificially constructed Habitats, and Ring Worlds.
Naturally habitable Planets come in nine basic climate types.
Some worlds that are currently uninhabitable may become habitable through Terraforming.
Entries that mention Habitable World
More in Exploration
Source: common/game_concepts (concept_habitable_world, also concept_habitable_worlds) and localisation/english, Stellaris Cygnus v4.5.2 (9776).