Meanings
- biologyPertaining to the side or surface around the mouth in an animal that has radial symmetry such as a starfish.
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 ...
1857, Professor Louis Agassiz, Natural History of North America, Vol. IV, page 376Antonyms: abactinal
- biologyPertaining to the axis of rotational symmetry in radiate animals.
[Professor Agassiz] gives the names of two axes of the animals; that around which the motion of the animal occurs is the actinal axis ...
1861, John Timbs, Charles W. Vincent, James Mason, The Year-book of Facts in Science and Art, Simpkin, Marshall, and Co., page 214
Synonyms & antonyms
adjectivePertaining to the side or surface around the mouth in an animal that has radial symmetry such as a starfish.
More synonyms by meaning
adjective(of radiate organisms) located on the surface or end on which the mouth is situated
Synonym sets from Open English WordNet, CC BY 4.0.
Origin
- Ancient Greekἀκτίς, ἀκτῖν-“ray”
- Englishactinal
From Ancient Greek ἀκτίς, ἀκτῖν- (aktís, aktîn-, “ray”) + -al. The usage was coined by Louis Agassiz (See quotations below.).
More words from Ancient Greek
Full word history & related roots →Rhymes & wordplay
Anagrams
Cite this entry
actinal. (n.d.). In WatkinsX Dictionary. Retrieved November 3, 2026, from https://dictionary.watkinsx.com/word/actinal
“actinal.” WatkinsX Dictionary, https://dictionary.watkinsx.com/word/actinal. Accessed November 3, 2026.
WatkinsX Dictionary, s.v. “actinal,” accessed November 3, 2026, https://dictionary.watkinsx.com/word/actinal.
Source: actinal on Wiktionary, CC BY-SA 4.0.