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• pyro
  pyro

  noun

  a pyromaniac.
• pyro-
  pyro-

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

pyro

¹ American  

[pahy-roh] / ˈpaɪ roʊ /

noun

Informal.

• pyros
  plural

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-.

Other Word Forms

Noun Inflected Forms

• pyros
  plural

Etymology

Origin of pyro¹

By shortening; cf. -o

Origin of pyro-²

< Greek pyro-, combining form of pŷr fire

Example Sentences

See Examples For:

pyro pyro- pyros

Every time you hit that pyro trigger, it’s “how much was that?”

From Los Angeles Times ● Apr. 30, 2026

Trying to pick out clear answers amid the fog of war and trophy-lift pyro isn't easy.

From BBC ● Mar. 14, 2026

It’s like half the normal film, and then they’ve integrated pyro and stuff happening live on a stage.

From Los Angeles Times ● Jul. 10, 2025

While supporters have mobilised independently of the club and fund their choreographies, banners and pyro displays, Hammarby's 'one-club' philosophy has certainly helped.

From BBC ● Nov. 11, 2024

Mix 30 drops pyro with from 30 to 60 drops bromide, then add 2 drachms ammonia solution and 2 drachms of water.

From Scientific American Supplement, No. 483, April 4, 1885 by Various

But enough of these follies: ‘Necro-, pyro-, geo-, hydro-, cheiro-, coscinomancy, With other vain and superstitious sciences.’

From Witch, Warlock, and Magician Historical Sketches of Magic and Witchcraft in England and Scotland by W. H. Davenport (William Henry Davenport) Adams

“For the really small ones it’s dark on that stage, there’s dry ice and pyros and it can be a bit frightening,’’ says Joseph.

From Newsweek

Seconds later, preignition pyros fired, igniting the main engines, and the MAV lurched upward.

From "The Martian" by Andy Weir

When electricity develops under the influence of heat, or is in any way connected with a rising or falling of temperature in a body, it is called "pyro-electricity," from the Greek word "pyros," fire.

From The Chemistry, Properties and Tests of Precious Stones by John Mastin

"I have tested Merck's pyro carefully in comparison with the other pyros at present on the market, and I find that it is superior to any and all of them."

From Photogravure by Henry R. Blaney

He is a monster whose destiny is providentially proclaimed by his name, for it is derived from the Greek word, pyros, which means fire.

From Penguin Island by Anatole France