Related Clues:

• It opens doors
• ''The Star-Spangled Banner'' author
• Something you may take in class
• Door unlocker
• Writer of ''The Star-Spangled Banner''
• It's taken in class
• Whole or half, in music
• Bit of music
• Good thing to have if a door is locked
• A student writes it
• B sharp, for one
• Something to take in class
• Something written in class
• It may have many X's and O's
• 'Do,' e.g., but not 'don't'