Briefly, "the realization that each random passerby is living a life as vivid and complex as your own." Originally from the Dictionary of Obscure Sorrows, which has a lot more beautiful neologism definitions like this you might enjoy.

An avid anime watcher. He wears glasses and rarely leaves his house. He works at a fast food place and has no girlfriend. He spends his money on video games and dresses like he's straight out of the 90's. If you ever meet a Terome, there's an 87% chance that he is gay so clench your buttholes when around him.