Related Clues:

• Whistler's whistle
• Full of feeling
• See 67-Across
• Song bit
• Harmonize
• Fix a flat?
• Bring to proper pitch
• Composer's creation
• Melody
• Word with in or out
• It may be hard to carry
• Ira Gershwin contribution
• Part of a libretto
• Musical number
• What whistlers whistle