pyrolysis

/paɪˈɹɒlɪsɪs/

//paɪˈɹɒlɪsɪs// noun

By · According to Wiktionary data (CC BY-SA) ·

"pyrolysis" is a 9-letter English headword indexed on PlainSpell.

The verdict

“pyrolysis” is uncommon English (frequency #65,428 among 46,516 “P” headwords), classed as a noun. The kind of spelling people second-guess.

#65,428
frequency rank, English
46,516
“P” headwords

According to Wiktionary data (CC BY-SA, analyzed May 6, 2026) - The decomposition of a material or compound due to heat, in the absence of oxygen or other reagents.

Key facts for pyrolysis
PropertyValue
Headwordpyrolysis
LanguageEnglish
Part of speechNoun
IPA/paɪˈɹɒlɪsɪs/
Letters9
Frequency rank#65,428
Misspellings tracked0
Confusable pairs0
SourceWiktionary (kaikki.org)

Where “pyrolysis” sits in English frequency

Every-word frequency runs from the handful of words we use constantly (left) to the long tail used once in a blue moon (right). pyrolysis lands here:

#1#100#1K#10K#100K
← used constantlyrarely used →

Scale is logarithmic (each tick is 10× rarer). Source: FrequencyWords open word-frequency list.

Rare enough to double-check

pyrolysis is uncommon English at frequency #65,428 among 46,516 “P” headwords, classed as anoun, transcribed /paɪˈɹɒlɪsɪs/. Rarity is why readers land here mid-draft. Gloss: "The decomposition of a material or compound due to heat, in the absence of oxygen or other reagents.".

pyrolysis has no tracked misspelling variants, typically a sign the spelling maps closely to how the word sounds. It is not paired with a close-neighbour confusable in our dataset, since its spelling is unusual enough that it doesn't cluster with a lookalike.

Etymologically, the entry records: From pyro- + -lysis. The correct English form is pyrolysis, spelled P-Y-R-O-L-Y-S-I-S.

Definition

  1. 1
    The decomposition of a material or compound due to heat, in the absence of oxygen or other reagents.

Etymology

From pyro- + -lysis.

This word in other languages

pirólisis(Español)pyrolyse(Français)Pyrolyse(Deutsch)

Definitions, pronunciation, and etymology for this entry are drawn from Wiktionary via the kaikki.org structured extract (CC BY-SA); frequency ordering uses the FrequencyWords open word-frequency list (2018 English corpus, MIT). See the methodology for how each field is sourced and updated.

Frequently Asked Questions

How do you spell "pyrolysis"?
"pyrolysis" is spelled P-Y-R-O-L-Y-S-I-S. The IPA pronunciation is /paɪˈɹɒlɪsɪs/.
What does "pyrolysis" mean?
As a noun, "pyrolysis" means: The decomposition of a material or compound due to heat, in the absence of oxygen or other reagents.
How do you pronounce "pyrolysis"?
The IPA (International Phonetic Alphabet) transcription for "pyrolysis" is /paɪˈɹɒlɪsɪs/. Click the speaker icon on the pronunciation badge above to hear it spoken aloud where audio is available.
What is the origin of the word "pyrolysis"?
From pyro- + -lysis. See the full etymology section above for more details.
Is PlainSpell free to use?
Yes, PlainSpell is a completely free word reference. You can look up definitions, pronunciations, confusable pairs, homophones, and spelling corrections across 5 languages without any sign-up or subscription.

Using “pyrolysis”

The practical upshot for anyone who landed here from a spell-check.

  • The one correct English spelling is P-Y-R-O-L-Y-S-I-S - every other letter order is a misspelling in standard orthography.
  • Say it as /paɪˈɹɒlɪsɪs/ (IPA); tap the speaker on the pronunciation badge to hear it where audio exists.
  • Browse more English words and confusable pairs in the same reference. English words

Other uncommon English words near this rank

Data Source

Wiktionary (via kaikki.org), licensed under CC BY-SA & GFDL. Word ordering uses an open word-frequency list; misspelling variants are generated by edit-distance from the correct headword.

Source: Wiktionary (via kaikki.org) Structured Wiktionary extract

Source: FrequencyWords open word-frequency list FrequencyWords open word-frequency list