A boy who is your main crush above all, hence ;thing 1; Usually crush lasts a few years, may have know him and previously talked to him, usually has a ugly girlfriend who resembles a guy and therefore makes your friends say you are better looking.
Girl 1- Ughh I have a new crush
Girl 2- Who?
Girl 1- Thing 1
Girl 2- Oh is he your main crush?
Girl 1- Yup