pyro

¹ American  

[pahy-roh] / ˈpaɪ roʊ /

noun

Informal.

plural

pyros

1. a pyromaniac.

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pyro- ² American  

1. a combining form meaning “fire,” “heat,” “high temperature,” used in the formation of compound words.

   pyrogen; pyrolusite; pyromancy.

2. Chemistry. a combining form used in the names of inorganic acids, indicating that the acid's water content is intermediate between that of the corresponding ortho- (more water) and meta- (least water) acids (pyroantimonic, H 4 Sb 2 O 7 , pyroarsenic, H 4 As 2 O 7 , and pyrosulfuric, H 2 S 2 O 7 ,acids ). The combining form is also used in the names of the salts of these acids. If the acid ends in -ic, the corresponding salt ends in -ate (pyroboric acid, H 2 B 4 O 7 , and potassium pyrobate, K 2 B 4 O 7 , or pyrosulfuric, H 2 S 2 O 7 , and pyrosulfate, N 2 S 2 O7 ); if the acid ends in -ous, the corresponding salt ends in -ite (pyrophosphorous acid, H 4 P 2 O 5 , potassium pyrophosphite, K 4 P 2 O5 ).

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pyro- British  

combining form

1. denoting fire, heat, or high temperature

   pyromania

   pyrometer

2. caused or obtained by fire or heat

   pyroelectricity

3. chem

   1. denoting a new substance obtained by heating another

      pyroboric acid is obtained by heating boric acid

   2. denoting an acid or salt with a water content intermediate between that of the ortho- and meta- compounds

      pyro-phosphoric acid

4. mineralogy

   1. having a property that changes upon the application of heat

      pyromorphite

   2. having a flame-coloured appearance

      pyroxylin

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Usage

What does pyro- mean? Pyro- is a combining form used like a prefix that has two distinct senses. The first of these senses is “fire,” "heat," or "high temperature," and this form of pyro- is occasionally used in a variety of scientific and technical terms. The second of these senses is used in terms from chemistry to mean “inorganic acids” or "the salt of inorganic acids."Pyro- in both of these senses comes from Greek pŷr, meaning “fire.” The Latin translations of pŷr are ignis and incendium, both of which also mean “fire” and are the sources of terms such as ignite and incendiary. To learn more, check out our entries for both words. What are variants of pyro-?When combined with words or word elements that begin with a vowel, pyro- becomes pyr-, as in pyric. Want to know more? Read our Words That Use article on pyr-.

Etymology

Origin of pyro¹

By shortening; -o

Origin of pyro-²

< Greek pyro-, combining form of pŷr fire

Example Sentences

An elaborate show featuring poetry, pyro and Frederic Michalak will precede the match.

From BBC • Mar. 14, 2026

It’s proof that you don’t need a semitruck full of pyro to be considered a generational entertainer.

From Seattle Times • Jun. 18, 2023

This process is called pyroptosis, from the Latin "pyro" for fire and the Greek "ptosis" for falling off, like the leaves of a tree.

From Salon • Nov. 2, 2022

“The pyro is on the grass,” she said.

From New York Times • Jul. 2, 2022

If one is using pyro, a fresh solution should be at once made up, using half the quantity of pyro given in the formula, and the full amount of the alkaline solution.

From Harper's Round Table, July 30, 1895 by Various