1. plural of pirarucu; large freshwater fish native to South America, valued as food and for sport fishing
Usage: Also spelled arapaima or pirarucu (singular); the plural form pirarucus is less common than the singular used as both singular and plural

Examples

• The fishermen caught several pirarucus in the Amazon River.
• Pirarucus are among the largest freshwater fish in the world.
• Local communities have traditionally hunted pirarucus for food.
• The aquarium displayed a collection of pirarucus in a large tank.