system
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human
[General] What exactly is the difference between "Psionic" and "Psychic"?

I see these two terms used interchangably. Even superpower wiki does this. Is there any fundamental difference between them in fiction?
gpt
Psionic usually refers to a type of mental ability that affects the physical world, either directly (telekinesis) or via the manipulation of some force or other phenomena (electrokinesis, pyrokinesis, etc). Psychic, on the other hand, refers to abilities that affects people mentally (telepathy, mind control), or offers some sort of extra-sensory perception (premonitions, psychometry).

In practice, however, the two terms are mainly just used interchangeably in most circumstances. As a general rule of thumb, psionics is favoured more by 'harder' works of science fiction while 'softer' works and more fantasy-like settings tend to go with psychic.