from The American Heritage® Dictionary of the English Language, 4th Edition
- adj. Of, relating to, or located on the part of a radially symmetric animal from which the tentacles radiate or the side where the oral area is found.
from Wiktionary, Creative Commons Attribution/Share-Alike License
- adj. Pertaining to the side or surface around the mouth in an animal that has radial symmetry such as a starfish.
- adj. Pertaining to the axis of rotational symmetry in radiate animals.
from the GNU version of the Collaborative International Dictionary of English
- adj. Pertaining to the part of a radiate animal which contains the mouth.
from The Century Dictionary and Cyclopedia
- In zoology: Pertaining to the side of a radiate animal which contains the mouth: equivalent to oral, since the pole, surface, or aspect of the body whence parts radiate is also that in which the mouth is situated: the opposite of abactinal or aboral.
- In general, having tentacles or rays.
from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
- adj. (of radiate organisms) located on the surface or end on which the mouth is situated
From Ancient Greek ἀκτίς, ἀκτῖν- (actis, actin-, "ray") + -al. The usage was coined by Louis Agassiz (See quotations below.). (Wiktionary)