worldbuilding

• world-building
• world building

world +‎ building

worldbuilding (uncountable)

1. The conception and description of a fictional world that is the setting of a work of fiction, particularly in fantasy and science fiction.
   • 2013 February 8, Charlie Jane Anders, “7 Deadly Sins of Worldbuilding”, in io9‎:

     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.

2. (obsolete) Scientific research into the creation of the Earth and its geological features.
3. (obsolete) The world of imagination of novelists, poets, etc.

• worldbreaking
• worldmaking

• “What is 'World-Building'? And how do you spell it?”, in Merriam-Webster‎, 2016