1. A phylum of aquatic invertebrate animals that includes jellyfish, sea anemones, and corals, characterized by a simple body structure with a single opening surrounded by tentacles.
Usage: biology; zoology; also called Cnidaria in modern classification

Examples

• Jellyfish are members of the phylum Coelentera.
• Sea anemones belong to the coelentera group of marine animals.
• The coelentera have existed in Earth's oceans for over 600 million years.
• Corals are colonial organisms within the coelentera phylum.
• Students learned that coelentera possess stinging cells called nematocysts.