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a combining form meaning “more,” used in the formation of compound words: pleomorphism.
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Also pleio-, plio-.

Origin of pleo-

Combining form representing Greek pleíōn more (comparative of polýs;see poly-); see -o-
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2022


What does pleo- mean?

Pleo– is a combining form used like a prefix meaning “more.” It is often used in scientific terms, especially in biology.

Pleo– comes from Greek pleíōn, meaning “more.” The Latin cognate of pleíōn is plūs “more,” which is the source of terms such as plural and plus. To learn more, check out our entries for these two words.

What are variants of pleo-?

In some rare instances, pleo– is spelled with an –i-, becoming pleio, as in pleiotropism. In even rarer cases, the –e– in pleo– is replaced with an –i-, becoming plio, as in pliotron. Want to know more? Read our Words That Use articles about pleio– and plio-.

Examples of pleo-

One example of a scientific term that features the form pleo– is pleochroic, meaning “characterized by pleochroism, a property of certain crystals of exhibiting different colors when viewed from different directions under light.”

As we have seen, pleo– means “more,” but what about the –chroic part of the word? The form chroic means “having a color,” from Greek chrṓs. Pleochroic literally translates to “having more colors.”

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

What are some other forms that pleo– may be commonly confused with?

Break it down!

Cytosis is a disorder of the cells. With this in mind, what does pleocytosis mean?

How to use pleo- in a sentence

  • Or by the assumption of an equivocal term, as in parocheken de pleo nux, where pleo in equivocal.

    The Poetics|Aristotle

British Dictionary definitions for pleo-


combining form
a variant of plio- pleochroism; pleomorphism
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