Hub and spoke
Also said as Hub world, Hub level, Overworld hub
A central place with levels or regions branching off it, so that the player returns to the middle and picks where to go next.
If one part is too hard, the player can do another. It also gives them one familiar home, which is why the shape shows up in theme parks as well as games. The cost is walking back through the centre.
Say it
“Players quit when the third level stops them. Change the line into a hub with four spokes, any three of which open the final door.”
Where you’ve seen it
Super Mario 64 uses Peach's Castle as a hub, with paintings leading to its courses. If a course is too hard you walk back and jump into another one. Disneyland is the same shape, with its lands around a central plaza.
Not to be confused with open world
A hub links separate places through one centre. An open world is one continuous place you can cross in any direction.