I define hygge as the experience, in a particular situation, of social relations and physical conditions that allow one to be present, in a way that feels unhurried and authentic.
One could also define hygge as an atmosphere that allows dwelling. My definition of hygge has simplified over time, as I have worked with the topic from different angles. Read earlier thoughts on a definition here.
I did PhD and post doc research on hygge. I carried out extensive ethnographic research on how Danes relate to home, togetherness and family life, and how hygge influences the consumption of leisure, hospitality, food and drinks. See some of my essays and talks on hygge here.