-oid

The suffix –oid 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.

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?

• benzenoid
• conoid (using the equivalent form of –oid in Greek)
• erythroid
• haploid
• osteoid

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

• -ode
• -oic

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