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The combining form –tropous is used like a suffix meaning “turned, curved” in the direction specified by the first part of the word. It is used in some scientific terms, especially botany.

The form -tropous comes from the Greek suffix –tropos, meaning “pertaining to a turn.” This suffix is based on �ٰ�ó��Dz�, “turn,” and �ٰ��DZ�ḗ, “a turning.”

The Greek �ٰ�ó��Dz� is also the source of the words trope and tropical. It’s your turn to make the connection between “turning,”  figures of speech, and the tropics at our entries for the words.

Closely related to -tropous is -tropic. The combining forms -tropy and -tropism are used to form abstract nouns from concrete nouns using -tropous and -tropic. Corresponding forms of -tropous combined to the beginning of words are tropo- and trop-. Learn more about their specific applications of our 51�Թ�s That Use articles for the forms.

An example of a scientific term that features -tropous is orthotropous, a term used in botany to describe an ovule that grows straight and symmetrically.

The first portion of the word, ortho-, means “straight, upright.” As we know, the second part of the word, -tropous, means “turned.” Orthotropous literally translates to “turned upright.”

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

• allotropous
• anatropous
• amphitropous
• isotropous

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

• -tomous
• -troph
• -trophic
• -trophy

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 as a multitude of others, from nervous to glorious—is not indicating “cut” or “divided.” Learn more at our entry for -ous.

Plant species described as allotropous can be pollinated by many types of insects. Given that allo- means “other,” what does allotropous literally translate to?