The name Actinozoa stems from the Greek words aktis (ray) and zoon (animal), referring to their radial symmetry and the "ray-like" appearance of their tentacles.

: They use tentacles armed with specialized stinging cells called nematocysts to capture prey, ranging from plankton to small fish.

Actinozoans are the primary architects of , which are among the most biodiverse ecosystems on Earth. Stony corals secrete calcium carbonate skeletons that form the structural foundation of these reefs, providing habitat for thousands of other marine species.

: The body consists of a central gastrovascular cavity divided by vertical partitions called mesenteries or septa. These mesenteries increase the surface area for digestion and support the gonads.

: While sea anemones are typically solitary, many Actinozoans (like reef-building corals) form massive colonies of interconnected clones. Classification

: Includes sea anemones and stony corals. They typically have tentacles and mesenteries in multiples of six.