CLEF KIND OF is a term used to describe the different types of clefs used in music notation. The solutions for the crossword are BASS (4 letters), TREBLE (6 letters), ALTO (4 letters), STAFF (5 letters), ALTOS (5 letters), VIOLA (5 letters), ROMAN (5 letters), and OBOE (4 letters). These clefs are used to indicate the pitch of the notes on a STAFF, with BASS and TREBLE being the most common. ALTO and ALTOS are also used to indicate the pitch of notes, but are less common than BASS and TREBLE. The VIOLA clef is used to indicate the pitch of notes for the VIOLA instrument. The ROMAN clef is used to indicate the pitch of notes for the violin instrument. Lastly, the OBOE clef is used to indicate the pitch of notes for the OBOE instrument.