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a combining form meaning “oblique,” used in the formation of compound words: plagioclase.
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Origin of plagio-

Combining form representing Greek plágios slanting, sideways, equivalent to plág(os) side + -ios adj. suffix
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2022


What does plagio- mean?

Plagio- is a combining form used like a prefix meaning “oblique” or “slanted.” It is used in some medical and scientific terms.

Plagio- comes from the Greek plágios, meaning “slanting” or “sideways.” The Greek plágios is also the source of plage, “a sandy bathing beach at a seashore resort.” More people might know the ultimate Spanish derivative of this Greek root: playa, meaning “beach.”

What are variants of plagio-?

When combined with words or word elements that begin with a vowel, plagio- becomes plagi-, as in plagihedral.

Examples of plagio-

One example of a medical term that features the combining form plagio- is plagiocephaly, “a deformity of the skull in which one side is more developed in the front, and the other side is more developed in the rear.” This condition is also known as flat head syndrome.

The first part of the word, plagio- means “slanted,” as we know. What about the -cephaly portion of the word? It means “having a head” of a specified kind. Plagiocephaly literally translates to “having a slanted head.”

What are some words that use the combining form plagio-?

What are some other forms that plagio- may be commonly confused with?

Not every word that begins with the exact letters plagi- is necessarily using the combining form plagio- to denote “oblique” or “slanted,” e.g., plagiarism. Learn about the history and meaning of plagiarism at our entry for the word.

Break it down!

The combining form -tropic means “turned toward” or “having an orientation toward.” How do plagiotropic plants grow, generally speaking?

British Dictionary definitions for plagio-


combining form
slanting, inclining, or obliqueplagiotropism

Word Origin for plagio-

from Greek plagios, from plagos side
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Medical definitions for plagio-


Slanting; inclining:plagiocephaly.
The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.