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a combining form meaning “cut, divided,” used in the formation of compound words: dichotomous.
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Origin of -tomous

<Greek -tomos.See -tome, -ous
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2023


What does -tomous mean?

The combining form -tomous is used like a suffix meaning “cut, divided.” It is used in some scientific and technical terms.

The form -tomous ultimately comes from the Greek tómos, meaning “cut, slice, piece, roll of paper, book.” This root is also the source of the word tome. Crack open the history of tome at our entry for the word.

Related to -tomous are the combining forms -ectomy, -tome, -tomy, and tomo-. Slice into their specific meanings at our Words That Use articles for the forms.

Also related to tómos is atom. What’s the big idea behind atoms and cutting? Find out in our Origin section for this term.

Examples of -tomous

One example of a word that features the combining form -tomous is dichotomous, “divided or dividing into two parts.”

The first part of the word, dicho-, is a combining form meaning “in two parts.” As we have seen, -tomous means “divided.” So, dichotomous literally translates to “divided in two parts.”

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

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

Keep in mind that -ous is a suffix used to form a great many words in English, from stupendous to stannous. While it is related to the -ous in -tomous, -ous in these words—as well a multitude of others, from nervous to glorious—is not indicating “cut” or “divided.” Learn more at our entry for -ous.

Break it down!

The combining form aniso- means “unequal” or “uneven.” With this in mind, what does anisotomous mean?  

How to use -tomous in a sentence