User blog comment:KpTroopaFR/Survey/Conworld Recruiting/@comment-26045265-20161016184845/@comment-26520756-20161016191506

Conlang : constructed language, the most famous ones being elvish, dothraki, klingon and Esperanto.

Conworld : constructed world, like Middle Earth.

Worldbuilding : both combined, you create a world, a culture, languages perhaps, etc.