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octo-

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variant of octa-: octosyllabic.
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Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2022

WORDS THAT USE OCTO-

What does octo- mean?

Octo- is a combining form used like a prefix meaning “eight.” It is used in a great many scientific and technical terms.

Octo- comes from te Greek oktṓ, meaning “eight.” The Latin equivalent, which is almost identical in spelling and pronunciation, is octō.

What are variants of octo-?

When combined with words or word elements that begin with a vowel, octo- becomes oct-, as in octane. Another variant of octo- is octa-, as in octastyle. Want to know more? Check out our Words That Use entries for both oct- and octa-.

Examples of octo-

An example of a word you may have encountered that features octo- is octopus, an animal “having a soft, oval body and eight sucker-bearing arms, living mostly at the bottom of the sea.” Octopus comes from Greek oktṓpous, which uses the equivalent of the form octo-.

The octo- portion of the word means “eight,” but the -pus part means “footed,” from Greek poús. Octopus literally translates to “eight-footed.”

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

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

Break it down!

Centenary means “a period of 100 years.” With this in mind, what is an octocentenary?

How to use octo- in a sentence

British Dictionary definitions for octo-

octo-

octa- or before a vowel oct-


combining form
eightoctosyllabic; octagon

Word Origin for octo-

from Latin octo, Greek okto
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
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