Names are indeed powerful. In myth and legend, certainly. Knowing the true name of something often gives you power over that thing. So your true name is sort of like your third cat name: the name that you never will guess; the name that no human research can discover - But the cat himself knows, and will never confess.

These secret true names are invoked in some games as a mechanism for controlling entities such as demons or spirits or djinn. That sort of thing often doesn't turn out very well for the controller though. If you're in a game and you ever find yourself in possession of the true name of a powerful being... take the better part of valour and forget you ever came across it.

Transcript

Luke: Or... just to pick something wildly at random that we don't need to hike to... How about we levitate my spaceship?
Yoda: But only one of her there is.
Luke: So I'll levitate while you push down. Opposed forces like a real arm-wrestle. Best of three.
Yoda: Hmm. Very well. Hee hee!
Luke: Okay, so it's a big ship. How do I do this?
Yoda: Feel the living Force.
Yoda: Names are powerful.
Yoda: All living things have a name. You... me... the aminals... the tree... the rock...
Luke: The rock?
Yoda: I saw it move once.