worldbuilding noun3 •The conception and description of a fictional world, often as the setting of a work of fiction, particularly in speculative fiction.The purpose of worldbuilding isn't just to do a cool exercise, but to give a sense of place — and all of your thought experiments absolutely have to result in something vivid and alive. — 2013 •(no longer used) The world of imagination of novelists, poets, etc. •(no longer used) Scientific research into the creation of the Earth and its geological features.