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
The presence of a brain is not essential, because acephalous monsters develop without brain, and they are born alive; they have a vital principle which is identical with the soul.
From Essays In Pastoral Medicine by Austin ?Malley
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
I cannot imagine anything more manifestly made to be a tyranny than such an acephalous aristocracy.
From What I Saw in America by G. K. (Gilbert Keith) Chesterton
The pearl-bearing oyster is of a more delicate nature than most of the other acephalous mollusca.
From Personal Narrative of Travels to the Equinoctial Regions of America, During the Year 1799-1804 — Volume 1 by Thomasina Ross
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.
