pyrolysis

/paɪˈɹɒlɪsɪs/

//paɪˈɹɒlɪsɪs// noun

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

The verdict

“pyrolysis” is uncommon English (frequency #65,428 among 4,417 “P” headwords), classed as a noun. The kind of spelling people second-guess.

#65,428
frequency rank, English
4,417
“P” headwords

According to Wiktionary data (CC BY-SA, analyzed September 3, 2026) - The decomposition of a material or compound due to heat, in the absence of oxygen or other reagents.

Corpus desk

Index EN-pyrolysis · pyrolysis · English

pyrolysis · rank #65,428 · 0 variants · 0 confusables

  • FREQ-RARE #65,428
  • LEN-LONG 9 letters
  • VOW-4 4 vowels
  • CONFUS-0 No pairs
  • VAR-0 0 variants
  • BOOK-MID 4,417
  • PHOTO-FINISH quackery

Nearest frequency peer: quackery (+1 rank slots)

Read with this headword: Spelling guide for this pattern

Desk codes from Wiktionary headword shape, FrequencyWords rank tier, confusable-pair count, generated misspelling depth, letter-cohort book size, and photo-finish peer. Not a difficulty grade.

Long-tail ranks near “pyrolysis”

Sparse band: bars invert rank so rarer forms read shorter

corpus weight

What this shows Long-tail view: where “pyrolysis” sits against similarly uncommon English ranks.

Source FrequencyWords open word-frequency list As of September 3, 2026
Key facts for pyrolysis
PropertyValue
Headwordpyrolysis
LanguageEnglish
Part of speechNoun
IPA/paɪˈɹɒlɪsɪs/
Letters9
Frequency rank#65,428
Misspellings tracked0
Confusable pairs0
SourceWiktionary (kaikki.org)

Long-tail rank of “pyrolysis” in English

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

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

The axis is logarithmic, with each marked tick roughly ten times rarer than the last. Rare peers in the same band: “quackery” (#65,429), “pyjama” (#65,426), “quali” (#65,430). Among 4,417 “P” headwords, “pyrolysis” is #65,428. Source: FrequencyWords open word-frequency list.

Rare enough to double-check

pyrolysis is uncommon English at frequency #65,428 among 4,417 “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.

Recorded use

Wiktionary examples

These source excerpts show how pyrolysis appears in context. They illustrate usage; the definition above remains the entry’s reference meaning.

  1. Techniques that have successfully identified ionic intermediates in solution have been applied to gas-phase pyrolyses.
  2. Twenty years ago our real understanding of the mechanism of alkane pyrolyses was little better than rudimentary.

Etymology

From pyro- + -lysis.

This word in other languages

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.

Similar English words by spelling shape

Same letter count and similar misspelling depth for "pyrolysis", not the corpus desk frequency band.

Same letter count

Frequency-ranked English headwords with 9 letters (nearest by frequency rank).

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

Source: FrequencyWords open word-frequency list