Related Clues:

• A choir may sing in it
• A type of bike
• Coincidence in pitch
• Lip-__
• Fit the sound to the action, e.g.
• Fit sound to action, e.g.
• Lip ---
• Lip- --
• Single-file
• Homophony
• Harmonization
• In __ (harmonized)
• Bicycle type
• Tandem
• Coordinate, digitally