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variant of pyro-, used before h or a vowel: pyran.
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Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2022


What does pyr- mean?

Pyr– 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 pyr– is very 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.”

Pyr– 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 pyr-?

When combined with words or word elements that begin with a consonant, pyr– becomes pyro, as in pyrogen. Want to know more? Read our Words That Use article on pyro-.

Not every word that begins with the exact letters pyr-, such as pyramid or pyrene, is necessarily using the combining form pyr– to denote “fire.” Learn why pyrene means “fruit stone” at our entry for the word.

Examples of pyr- with the sense “fire” or "heat"

One example of a medical term that uses the form pyr– is pyrosis, also known as heartburn, “an uneasy burning sensation in the stomach.” The word pyrosis comes from Greek pȳrōsis, which uses the equivalent of the form pyr– in that language.

The pyr– part of the word means “heat,” and the suffix osis is used to denote disorders or abnormal states. Pyrosis literally translates to “heat disorder.”

What are some words that use the equivalent of the combining form pyr– in Greek?

What are some other forms that pyr– may be commonly confused with?

Break it down!

The suffix ite is used to name minerals. With this in mind, what does pyrite literally mean?

Examples of pyr- with the sense “inorganic acids” or "the salt of inorganic acids"

A term that features the form pyr– in the sense of “inorganic acids” is pyridine, “a colorless, flammable, liquid organic base, C5H5N, having a disagreeable odor.”

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

What are some other forms that pyr– may be commonly confused with?

Break it down!

The word phosphoric means “containing phosphorus.” With this in mind, what is a pyrophosphoric chemical compound?

How to use pyr- in a sentence

British Dictionary definitions for pyr-


combining form
a variant of pyro-
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Medical definitions for pyr-


Variant ofpyro-
The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.