What is the definition of radial symmetry?

Radial symmetry:

1. Sessile and bottom-dwelling organisms, such as sea anemones and starfish, have a fundamental body plan in which the organism can be divided into comparable halves by passing a plane at any angle along a central axis.
2. The body of a person with radial symmetry has the general shape of a short or long cylinder or bowl, with a central axis from which the body parts radiate or are arranged in a regular pattern.
3. As a result, the major axis is known as the oral-aboral (or anteroposterior) axis.
4. Any plane crossing across this axis will divide the animal into symmetrical halves unless the species has an odd number of pieces organized in a circular pattern (as in the five-armed sea stars).
5. Cnidarians (including jellyfish and coral) and echinoderms have radial symmetry (such as sea urchins, and brittle stars).