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variant of zoo- before a vowel: zooid.
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Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2023


What does zo- mean?

The combining form zo– is used like a prefix meaning “living being” or “animal.” It is very occasionally used in scientific terms, especially in biology.

The form zo– comes from Greek zôion, meaning “animal.” The word zoo also ultimately comes from this Greek root. Zoo is shortened from zoological garden.

What are variants of zo-?

The form zo– is a variant of zoo, which loses its –o– when combined with words or word elements beginning with vowels.

When combined as a suffix, zo– becomes zoa or zoon, as in protozoa or ectozoon. Want to know more? Read our Words That Use articles for zoo-, –zoa, and –zoon.

Examples of zo-

One example of a scientific term that uses the form zo– is zooid, “any organic body or cell capable of spontaneous movement and of an existence more or less apart from or independent of the parent organism.”

The zo– part of the word means “animal,” as we have seen. The oid portion of the word means “resembling” and “like.” Zooid literally translates to “animal-like.”

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

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

Not every word that begins with the exact letters zoo– or zo-, such as zoom or zooty, is necessarily using either combining form to denote “animal.” Learn why zooty means “flamboyant” at our entry for the word.

Break it down!

The suffix ic is used to mean “having some characteristics of.” With this in mind, what does zoic mean?

How to use zo- in a sentence

British Dictionary definitions for zo- (1 of 2)


zho or dzo

/ (zəʊ) /

noun plural zos, zhos, dzos, zo, zho or dzo
a Tibetan breed of cattle, developed by crossing the yak with common cattle

Word Origin for zo

C20: from Tibetan

British Dictionary definitions for zo- (2 of 2)


combining form
a variant (before a vowel) of zoo-
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