any small, spiny-finned, sharklike fish of the extinct order Acanthodii, from the Paleozoic Era.
There is no evidence that the lateral row of spines in the acanthodian Climatius has any other than a defensive significance.
Encyclopaedia Britannica, 11th Edition, Volume 14, Slice 3 Various
spiny; spinous. adjective resembling a spine; spiny acanthoid a·can·thoid (ə-kān’thoid’) adj. Shaped like a thorn or spine.
the study of spines, as in sea urchins or certain spiny-headed worms, particularly as they relate to taxonomic classification. noun the scientific study of spines Word Origin Greek ‘thorn’
acantholysis acantholysis ac·an·thol·y·sis (āk’ān-thŏl’ĭ-sĭs, āk’ən-) n. pl. ac·an·thol·y·ses (-sēz’) Separation of individual prickle cells from their neighbors, as in keratosis follicularis.
acanthoma acanthoma ac·an·tho·ma (āk’ān-thō’mə, āk’ən-) n. pl. ac·an·tho·mas or ac·an·tho·ma·ta (-mə-tə) A tumor composed of epidermal squamous cells.