acephalous
Americanadjective
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Zoology. Also acephalic headless; lacking a distinct head.
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without a leader or ruler.
adjective
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having no head or one that is reduced and indistinct, as certain insect larvae
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having or recognizing no ruler or leader
Etymology
Origin of acephalous
1725–35; < Greek aképhalos; see a- 6, -cephalous
Explanation
Anything that is acephalous is headless — like the acephalous horseman of folklore. The term acephalous refers to organisms that lack a head, or to a group or society with no leader, or "head." Clams, oysters, mussels, and scallops are acephalous, as are sea stars, sea urchins, and sponges. Some historical tribal societies were acephalous: they had no one formal, decision-making authority. Leaderless digital communities and music bands are acephalous. The term is also used in poetry: An acephalous line is missing its first syllable based on an expected metrical pattern — e.g., "da-DUM da-DUM" becomes "DUM da-DUM." The term acephalous comes from Greek, where a- means "without" and kephalē means "head."
Example Sentences
Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.
The great development of mantle in the acephalous molluscs has rendered eyes, and even a head, entirely useless to them.
From Evolution, Old & New Or, the Theories of Buffon, Dr. Erasmus Darwin and Lamarck, as compared with that of Charles Darwin by Samuel Butler
A curious question arose in the instance of the girl, as to whether the extreme unction should be administered to the acephalous fetus as well as to the child.
From Anomalies and Curiosities of Medicine by Walter L. (Walter Lytle) Pyle
Such a cabinet ought not to be acephalous.
From The Life of William Ewart Gladstone (Vol 2 of 3) by John Morley
Almost all bivalve shells, or those of acephalous mollusca, are marine, about sixteen only out of 140 genera being fresh-water.
From The Student's Elements of Geology by Sir Charles Lyell
There is nothing more audacious in the poet's conception of the worm looking up towards humanity, than the naturalist's theory that the progenitor of the human race was an acephalous mollusk.
From Ralph Waldo Emerson by Oliver Wendell Holmes
Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023
Idioms from The American Heritage® Idioms Dictionary copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.
