endorphin

/ɛnˈdɔːfɪn/

//ɛnˈdɔːfɪn// noun

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

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

The verdict

“endorphin” is uncommon English (frequency #70,637 among 2,246 “E” headwords), classed as a noun. The kind of spelling people second-guess.

#70,637
frequency rank, English
2,246
“E” headwords

According to Wiktionary data (CC BY-SA, analyzed September 3, 2026) - Any of a group of peptide hormones found in the mammalian brain that act as neurotransmitters and have properties similar to morphine.

Corpus desk

Index EN-endorphin · endorphin · English

endorphin · rank #70,637 · 0 variants · 0 confusables

  • FREQ-RARE #70,637
  • LEN-LONG 9 letters
  • VOW-3 3 vowels
  • CONFUS-0 No pairs
  • VAR-0 0 variants
  • BOOK-MID 2,246
  • PHOTO-FINISH endeavouring

Nearest frequency peer: endeavouring (-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 “endorphin”

Sparse band: bars invert rank so rarer forms read shorter

corpus weight

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

Source FrequencyWords open word-frequency list As of September 3, 2026
Key facts for endorphin
PropertyValue
Headwordendorphin
LanguageEnglish
Part of speechNoun
IPA/ɛnˈdɔːfɪn/
Letters9
Frequency rank#70,637
Misspellings tracked0
Confusable pairs0
SourceWiktionary (kaikki.org)

Long-tail rank of “endorphin” in English

This scale runs from the tiny cluster of words that carry ordinary speech (left) to the long tail of words almost nobody reaches for (right).endorphinfalls 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: “endeavouring” (#70,636), “ennobled” (#70,639), “Enya” (#70,640). Among 2,246 “E” headwords, “endorphin” is #70,637. Source: FrequencyWords open word-frequency list.

Rare enough to double-check

endorphin is uncommon English at frequency #70,637 among 2,246 “E” headwords, classed as anoun, transcribed /ɛnˈdɔːfɪn/. Rarity is why readers land here mid-draft. Gloss: "Any of a group of peptide hormones found in the mammalian brain that act as neurotransmitters and have properties similar to morphine.".

endorphin doesn't appear in our generated misspelling index, a sign its spelling follows regular English conventions. No close-neighbour confusable shows up for this headword in our dataset, a sign it's visually distinctive enough not to be mixed up with another word.

Etymologically, the entry records: Borrowed from French endorphine, from endo(gène) (“endogenous, produced within”) and morphine. The correct English form is endorphin, spelled E-N-D-O-R-P-H-I-N.

Definition

  1. 1
    Any of a group of peptide hormones found in the mammalian brain that act as neurotransmitters and have properties similar to morphine.

Recorded use

Wiktionary example

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

  1. The explanation for the depression-reducing effects of exercise that clearly has been the most popular with the media is the endorphin hypothesis (see Hoffmann, 1997), which has also been discussed as a possible explanation in nearly every exercise-depression literature review.

Etymology

Borrowed from French endorphine, from endo(gène) (“endogenous, produced within”) and morphine.

This word in other languages

endorfina(Español)endorphine(Français)Endorphin(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 "endorphin"?
"endorphin" is spelled E-N-D-O-R-P-H-I-N. The IPA pronunciation is /ɛnˈdɔːfɪn/.
What does "endorphin" mean?
As a noun, "endorphin" means: Any of a group of peptide hormones found in the mammalian brain that act as neurotransmitters and have properties similar to morphine.
How do you pronounce "endorphin"?
The IPA (International Phonetic Alphabet) transcription for "endorphin" is /ɛnˈdɔːfɪn/. 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 "endorphin"?
Borrowed from French endorphine, from endo(gène) (“endogenous, produced within”) and morphine. 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 "endorphin", not the corpus desk frequency band.

Same letter count

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

Epictetus#70,642formulary#70,671Frankland#70,674cytometry#70,592

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

Source: FrequencyWords open word-frequency list