Book or movie lovers are able to get transported into another world, another reality, and be able to dive into the world with unique characters. Seeing how the world works from their point of view, feel their emotions, and go on an adventure with them through their eyes.
Have you ever felt as an individual like you long for a place or home that you feel this immense connection to? That if you went there all of your worries would wash away and you would just be happy living in the moment, not worrying about anyone, but yourself. Worlds like being a student harnessing their magical powers at a school for witches and wizards, being the captain of the most dangerous and merciless pirate crew sailing the seven seas, being a mystical underwater creature exploring the human world for the first time, navigating being a queen while being married to the next king of France, or even being the greatest female assassin tasked with killing the prince of a rivalry kingdom. All of the different and unique worlds have a variety of stories and adventures to experience. One way or another you establish this emotional connection with the characters or even just your favorite, feeling this sort of connection to that world.
There is a word for that feeling of longing to be at that home, it is called hireath. It means a homesickness for a home to which you cannot return to, a home which maybe never was; the nostalgia, the yearning, the grief for the lost places of your past. When you see or read about these different realities and one that just struck you so hard, like you meant to be there and not in this one, you are experiencing hireath.