Square (slang)
From Academic Kids
In the parlance of jazz, a square was a person who failed to appreciate the medium, i.e. one who was out of date or out of touch. The term has persisted and permeated into mainstream cultures, as exemplified in Elvis Costello's hit Hip to be square, which, in ultimate self-reference, was used by Sesame Street to illustrate the geometrical meaning of "square".
