trop

Trop- is a combining form used like a prefix variously meaning “turn,” “reaction, response,” or “change.” It is used in some technical terms.

Trop- ultimately comes from the Greek trópos, “turn,” and tropḗ, “a turning.” The Greek trópos 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.

Trop– is a variant of tropo-, which loses its –o– when combined with words or word elements beginning with vowels.

Want to know more? Read our Words That Use tropo– article. 

Corresponding forms of trop- and tropo- combined to the end of words are -trope, -tropic, -tropism, –tropous, and –tropy. Learn about their specific applications in our Words That Use articles for the forms.

An example of a scientific term that features the combining form trop- is tropism, “an orientation of an organism to an external stimulus, as light, especially by growth rather than by movement.”

The first part of the word, trop-, can indicate “reaction, response.” The second part of the word, -ism, can denote an “action or practice.” Tropism, then, literally translates to “act of reacting,” referring to how organisms that display tropism are responding to external stimuli.

What are some words that use or are related to the combining form trop-?

• esotropia
• exotropia
• hypertropia
• tropia

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

• top-
• troph-

The French trop, meaning “too, too much, too many,” is entirely spelled with the same letters as trop-, but the two forms are unrelated.

Exotropia (exo-, “outside”) is a vision disorder condition where one or both eyes turn outward. Given that the combining form eso- means “inner,” what is esotropia?