[OP: ]
When one talks about who is the strongest person on the human planet, they would say names like The Northern Witch, the Masters of the East, the Weapon masters of the North or the Headmaster.
They would call out big names, and if the context is changed just a little bit, they would call out names like the Mistress of Lakmer, the Grandmaster Creators, and those involved in the actual functioning of the world.
The 'Power' that they talk about in this way could be interpreted as many things.
Raw strength, stats, skills, abilities, powers to do something and the power to Not do something.
It could be anything and depending on the diverse interpretations, they could very well just call being a Child that knows nothing of this world the 'greatest' power there is.
-Boooooooooooooom!
But the people wouldn't understand the abstractness of such concepts.