Related Clues:

• Palo __
• Melchior, for one
• Orfeo, e.g., in Gluck's 'Orfeo ed Euridice'
• Caruso, notably
• Voice above a tenor
• Part of SATB
• She's low
• Word on a Mexican stop sign
• Hymn part
• "Nessun dorma" singer
• Clef type
• Certain sax
• One whose range typically starts at F below middle C
• Motet part
• Middle sax?