therm

/θɜːm/

//θɜːm// noun

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

"therm" is a 5-letter English headword indexed on PlainSpell.

The verdict

“therm” is uncommon English (frequency #95,510 among 27,828 “T” headwords), classed as a noun. The kind of spelling people second-guess.

#95,510
frequency rank, English
27,828
“T” headwords

According to Wiktionary data (CC BY-SA, analyzed May 6, 2026) - A unit of heat equal to 100,000 British thermal units, often used in the context of natural gas.

Key facts for therm
PropertyValue
Headwordtherm
LanguageEnglish
Part of speechNoun
IPA/θɜːm/
Letters5
Frequency rank#95,510
Misspellings tracked0
Confusable pairs0
SourceWiktionary (kaikki.org)

Where “therm” 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). therm 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

therm is uncommon English at frequency #95,510 among 27,828 “T” headwords, classed as anoun, transcribed /θɜːm/. Rarity is why readers land here mid-draft. Gloss: "A unit of heat equal to 100,000 British thermal units, often used in the context of natural gas.".

No generated misspelling entries exist for therm in our index, a straightforward case of a spelling with little room for common typos. This headword has no recorded confusable partner, since nothing in our dataset looks or sounds close enough to cause mix-ups.

Etymologically, the entry records: 1920s, from Ancient Greek θερμός (thermós, “heat”). See also thermo-, -thermic, etc. The correct English form is therm, spelled T-H-E-R-M.

Definition

  1. 1
    A unit of heat equal to 100,000 British thermal units, often used in the context of natural gas.

Etymology

1920s, from Ancient Greek θερμός (thermós, “heat”). See also thermo-, -thermic, etc.

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 "therm"?
"therm" is spelled T-H-E-R-M. The IPA pronunciation is /θɜːm/.
What does "therm" mean?
As a noun, "therm" means: A unit of heat equal to 100,000 British thermal units, often used in the context of natural gas.
How do you pronounce "therm"?
The IPA (International Phonetic Alphabet) transcription for "therm" is /θɜːm/. 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 "therm"?
1920s, from Ancient Greek θερμός (thermós, “heat”). See also thermo-, -thermic, etc. 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 “therm”

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

  • The one correct English spelling is T-H-E-R-M - every other letter order is a misspelling in standard orthography.
  • Say it as /θɜːm/ (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