Thread: How is somebody powerful?
One trend you'll notice with anyone who has "power" in Tolkien's world is they are very strong willed. So while I wouldn't say this is the definition of "power," but it does mean it's more of a mental/invisible sort of power.
Of course you have Gandalf creating fire from his staff or creating a little lamp. And we're told he tried to set a defense spell on the door to stop the balrog in Moria but Durin's Bane countered it. And Melian had her girdle of power, which as far as we know doesn't mean instant lightning bolt to anyone inside it but rather she used it to confuse any who entered, either leading them out or to their doom.
So this could be another instance of Tolkien leaving it open to your interpretation. What does power mean to you? Galadriel was recognized as one of the most powerful beings in Middle Earth, and that's taking into account the Istari and other elves...but what exactly was her power? We don't have much record of her fighting or as a great soldier, but it's obvious her presence is more than enough to know she is capable of something extraordinary.
So I think it's intentionally left open like that. Maybe his point is there isn't only one type of power...