noun
- A taxonomic rank in biological classification that falls below the order and above the family.
Usage: technical; biology
Examples
- In mammalian classification, Infraorder Eutheria contains all placental mammals.
- The infraorder is a useful rank for organizing large and diverse orders into smaller groups.
- Primates belong to the infraorder Simiiformes within the order Primates.
- Biologists use the infraorder rank to clarify relationships between families that share a common ancestor.
- The infraorder Cetacea includes whales, dolphins, and porpoises.