1. A stinging cell found in jellyfish, sea anemones, and other cnidarians, containing a coiled harpoon-like structure used to capture prey or defend against predators.
Usage: biology; plural: cnidae or cnidas

Examples

• The jellyfish's tentacles are covered with thousands of cnidae that deliver venom to prey.
• Each cnida contains a coiled filament that can be rapidly discharged.
• Sea anemones use cnidae to paralyze small fish and other organisms.
• Under a microscope, the cnida's harpoon-like structure is clearly visible.
• The cnida is a specialized organelle unique to the phylum Cnidaria.