Feasts when "Dayenu" is sung

• Mid-Nisan feasts
• Wine-drinking, egg-eating rituals
• Passover celebrations
• Ritual meals
• Dinners at which people read at the table
• "Why is this night different ...?" nights
• Ceremonial feasts
• Matzo meals
• Ritual dinners

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