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a combining form meaning “horn,” “cornea,” used in the formation of compound words: keratogenous.
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Also especially before a consonant, cerato- Also especially before a vowel, kerat-, cerat- .

Origin of kerato-

From Greek kerāto-, combining form of kéras; akin to Latin cornū “horn”; see cornu, horn
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2023


What does kerato- mean?

Kerato- is a combining form used like a prefix meaning “horn” or “cornea.” The cornea is the transparent front part of the eyeball. It is used in some scientific and medical terms, including in ophthalmology and dermatology.

Kerato- comes from the Greek kéras, meaning “horn.” The Latin cousin to kéras is cornū, source of corneus, literally “horn-y.” The term cornea comes from the Latin phrase cornea tēla, meaning “horn-y web,” i.e., “hornlike tissue.”

Another word related to this Greek root is karat, or carat, which is a unit of weight for gemstones. It ultimately comes from the Greek word for “little horn.”

What are variants of kerato-?

When combined with words or word elements that begin with a vowel, kerato- becomes kerat-, as in keratin.

Kerato- and kerat- can also be spelled with an initial c-, becoming cerato- or cerat-, as in keratoid or ceratoid. Variants spelled with c- are pronounced with a soft c sound, e.g., [ seruh-toid ]. Learn more at our Words That Use articles for the forms.

Examples of kerato-

Keratotomy, meaning “incision of the cornea,” is one example of a medical term that features the combining form kerato-.

As we know, kerato- represents “cornea.” The second portion of the word, -tomy means “incision, cut.” Keratotomy literally translates to “cornea incision.”

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

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

Break it down!

The combining form -meter means “measure” and is used to name measuring instruments. What, generally speaking, is the medical instrument keratometer used for?

British Dictionary definitions for kerato-


before a vowel kerat-

combining form
indicating horn or a horny substancekeratin; keratogenous
indicating the corneakeratoplasty

Word Origin for kerato-

from Greek kerat-, keras horn
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