(n.) A basement brother is a male adult, usually between the ages of 22 to 45, who lives in a room in his parent's basement because he either can't afford to live on his own or chooses not to live on his own. The basement brother may be employed or unemployed, educated or uneducated. He is most likely unmarried and single. A basement brother is more likely to be found living in a small town or in the suburbs than in a large city. He is usually a loner. He typically spends his time watching TV, using the Internet, playing video games, reading, sleeping, and reminiscing about the "good ol' days" when he was in his teens or early twenties when the future looked bright and he still believed he was going to make something of himself.
I have a 35-year-old basement brother back in Arkansas who divides his waking hours playing video games and reading philosophy books.