The term 'Bass Symbol' is a reference to the musical CLEF, which is a symbol used to indicate the pitch of written notes. The CLEF is typically represented by a four-letter word, such as 'CLEF, ' and is used to denote the range of notes that can be played on a particular instrument. In the case of bass instruments, the CLEF is usually a bass CLEF, which is a stylized letter 'F' that indicates the lower range of notes.