Save This Word!

a suffix meaning “resembling,” “like,” used in the formation of adjectives and nouns (and often implying an incomplete or imperfect resemblance to what is indicated by the preceding element): alkaloid; anthropoid; cardioid; cuboid; lithoid; ovoid; planetoid.
There's an ocean of difference between the way people speak English in the US vs. the UK. Are your language skills up to the task of telling the difference? Let's find out!
Question 1 of 7
True or false? British English and American English are only different when it comes to slang words.
Compare -ode1.

Origin of -oid

<Greek -oeidēs, equivalent to -o--o- + -eidēs having the form of, derivative of eîdos form
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2023


What does -oid mean?

The suffixoid means “resembling” or “like.” It is often used in scientific terms, especially in biology.

The suffix –oid comes from Greek –oeidēs, from eîdos meaning “form.”

What are variants of –oid?

The plural form of –oid used in the names of zoological classes is oidea, as in cynoidea. Want to know more? Read our Words That Use article on –oidea.

Examples of -oid

An example of a word you may have encountered that features oid is
factoid, “an insignificant or trivial fact.” It also refers to something presented as fact but is not necessarily true.

The fact part of the word here literally means “fact,” as in “something that actually exists.” The suffix –oid means “resembling,” as we have seen. Factoid literally means “resembling a fact.”

What are some words that use the suffix –oid?

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

Break it down!

The combining form oste means “bone.” With this in mind, what does osteoid literally mean?

How to use -oid in a sentence

British Dictionary definitions for -oid


suffix forming adjectives, suffix forming nouns
indicating likeness, resemblance, or similarityanthropoid

Word Origin for -oid

from Greek -oeidēs resembling, form of, from eidos form
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

Scientific definitions for -oid


A suffix meaning “like” or “resembling,” as in ellipsoid, a geometric solid that resembles an ellipse.
The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.