actinal

From Ancient Greek ἀκτίς, ἀκτῖν- (aktís, aktîn-, “ray”) +‎ -al. The usage was coined by Louis Agassiz (See quotations below.).

actinal

1. (zoology) Pertaining to the side or surface around the mouth in an animal that has radial symmetry such as a starfish.
   • 1857, Professor Louis Agassiz, Natural History of North America, Vol. IV, page 376:

     The so-called mouth is always placed at one of these poles, and from it radiate the most prominent organs, in consequence of which I have called this side of the body the oral or actinal area ...

2. (zoology) Pertaining to the axis of rotational symmetry in radiate animals.
   • 1861, John Timbs, Charles W. Vincent, James Mason, The Year-book of Facts in Science and Art, Simpkin, Marshall, and Co., page 214,

     [Professor Agassiz] gives the names of two axes of the animals; that around which the motion of the animal occurs is the actinal axis ...

• abactinal

• alicant, antical