It's different for everyone. And it is not tangible... It's a state of being.

[He hums, thoughtful... Perhaps he has some examples.]

Listening to Guizhong work on her inventions. Watching Azhdaha bask in the sunlight he went for so long without. Listening to me tell a story that's been heard dozens upon dozens of times.

Being beside someone and co-existing around one another. I believe that is harmony between two people.