Group of like voices

• Choir members
• Domingo and Pavarotti
• Barbershop quartet members
• Some singers at the Met
• "Some of the knights in Wagner's "Tannh"
• Roy Orbison and Marvin Gaye, e.g.
• Domingo et al
• Domingo, Carrera, and Pavarotti, famously
• Domingo and Vickers

Wiktionary Word definitions in Wiktionary
n. (plural of tenor English)