Eminem coined the term “Stan” when he released his single “Stan” featuring Dido on November 21, 2000. The single was about an obsessed fan who was/is in love with him. Since then “Stan” has been used to describe a super fan. The word “Stan” got so big and cemented that it was even added to the Oxford American Dictionary in 2017.
The Merriam-Webster Dictionary added the word “Stan” to its database on April 23, 2019 as both a noun (“an extremely or excessively enthusiastic and devoted fan”) and a verb (“to exhibit fandom to an extreme or excessive degree” or “to be an extremely devoted and enthusiastic fan of someone or something”).
The singer Dido who was featured on the song, ended up naming her first son Stanley.
Read: What does “Stan” mean?