prolactin

/pɹoʊˈlæktɪn/

//pɹoʊˈlæktɪn// noun

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

The verdict

“prolactin” is uncommon English (frequency #61,728 among 4,417 “P” headwords), classed as a noun. The kind of spelling people second-guess.

#61,728
frequency rank, English
4,417
“P” headwords

According to Wiktionary data (CC BY-SA, analyzed September 3, 2026) - A peptide gonadotrophic hormone secreted by the pituitary gland; it stimulates growth of the mammary glands and lactation in females.

Corpus desk

Index EN-prolactin · prolactin · English

prolactin · rank #61,728 · 0 variants · 0 confusables

  • FREQ-RARE #61,728
  • LEN-LONG 9 letters
  • VOW-3 3 vowels
  • CONFUS-0 No pairs
  • VAR-0 0 variants
  • BOOK-MID 4,417
  • PHOTO-FINISH profligate

Nearest frequency peer: profligate (-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 “prolactin”

Sparse band: bars invert rank so rarer forms read shorter

corpus weight

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

Source FrequencyWords open word-frequency list As of September 3, 2026
Key facts for prolactin
PropertyValue
Headwordprolactin
LanguageEnglish
Part of speechNoun
IPA/pɹoʊˈlæktɪn/
Letters9
Frequency rank#61,728
Misspellings tracked0
Confusable pairs0
SourceWiktionary (kaikki.org)

Long-tail rank of “prolactin” in English

Word frequency stretches from the small set of words we reach for constantly (left) out to the long tail barely used once in a while (right).prolactinfalls in this rarity band:

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

Scale is logarithmic (each tick is 10× rarer). Rare peers in the same band: “profligate” (#61,727), “processional” (#61,726), “proteomics” (#61,730). Among 4,417 “P” headwords, “prolactin” is #61,728. Source: FrequencyWords open word-frequency list.

Rare enough to double-check

prolactin is uncommon English at frequency #61,728 among 4,417 “P” headwords, classed as anoun, transcribed /pɹoʊˈlæktɪn/. Rarity is why readers land here mid-draft. Gloss: "A peptide gonadotrophic hormone secreted by the pituitary gland; it stimulates growth of the mammary glands and lactation in females.".

The misspelling generator found no plausible variants for prolactin, typically a sign the spelling maps closely to how the word sounds. This headword has no recorded confusable partner, which typically means the spelling is too distinctive to be mistaken for another word.

Etymologically, the entry records: From pro- (from Ancient Greek πρό (pró, “before”)) + lact- (variation of lacto-, from Latin lac (“milk”)) + -in (modification of -ine). The correct English form is prolactin, spelled P-R-O-L-A-C-T-I-N.

Definition

  1. 1
    A peptide gonadotrophic hormone secreted by the pituitary gland; it stimulates growth of the mammary glands and lactation in females.

Recorded use

Wiktionary example

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

  1. Men get a dose of the hormone prolactin after orgasm and this acts as a sedative.

Etymology

From pro- (from Ancient Greek πρό (pró, “before”)) + lact- (variation of lacto-, from Latin lac (“milk”)) + -in (modification of -ine).

Synonyms

lactotropinluteotropic hormoneluteotropinmammotropin

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 "prolactin"?
"prolactin" is spelled P-R-O-L-A-C-T-I-N. The IPA pronunciation is /pɹoʊˈlæktɪn/.
What does "prolactin" mean?
As a noun, "prolactin" means: A peptide gonadotrophic hormone secreted by the pituitary gland; it stimulates growth of the mammary glands and lactation in females.
How do you pronounce "prolactin"?
The IPA (International Phonetic Alphabet) transcription for "prolactin" is /pɹoʊˈlæktɪn/. 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 "prolactin"?
From pro- (from Ancient Greek πρό (pró, “before”)) + lact- (variation of lacto-, from Latin lac (“milk”)) + -in (modification of -ine). 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 "prolactin", 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