bilirubin

/bɪlɪˈɹuːbɪn/

//bɪlɪˈɹuːbɪn// noun

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

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

The verdict

“bilirubin” is uncommon English (frequency #65,730 among 4,121 “B” headwords), classed as a noun. The kind of spelling people second-guess.

#65,730
frequency rank, English
4,121
“B” headwords

According to Wiktionary data (CC BY-SA, analyzed September 3, 2026) - A bile pigment that is a product of the breakdown of the heme portion of hemoglobin (which occurs within macrophages as they digest red blood cells), and which is responsible for the yellowish colo...

Corpus desk

Index EN-bilirubin · bilirubin · English

bilirubin · rank #65,730 · 0 variants · 0 confusables

  • FREQ-RARE #65,730
  • LEN-LONG 9 letters
  • VOW-4 4 vowels
  • CONFUS-0 No pairs
  • VAR-0 0 variants
  • BOOK-MID 4,121
  • PHOTO-FINISH biked

Nearest frequency peer: biked (-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 “bilirubin”

Sparse band: bars invert rank so rarer forms read shorter

corpus weight

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

Source FrequencyWords open word-frequency list As of September 3, 2026
Key facts for bilirubin
PropertyValue
Headwordbilirubin
LanguageEnglish
Part of speechNoun
IPA/bɪlɪˈɹuːbɪn/
Letters9
Frequency rank#65,730
Misspellings tracked0
Confusable pairs0
SourceWiktionary (kaikki.org)

Long-tail rank of “bilirubin” 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).bilirubinfalls 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: “biked” (#65,729), “billionth” (#65,731), “Besson” (#65,728). Among 4,121 “B” headwords, “bilirubin” is #65,730. Source: FrequencyWords open word-frequency list.

Rare enough to double-check

bilirubin is uncommon English at frequency #65,730 among 4,121 “B” headwords, classed as anoun, transcribed /bɪlɪˈɹuːbɪn/. Rarity is why readers land here mid-draft. Gloss: "A bile pigment that is a product of the breakdown of the heme portion of hemoglobin (which occurs within macrophages as they digest red blood cells), and which is responsible for the yellowish colo...".

No generated misspelling entries exist for bilirubin in our index, a sign its spelling follows regular English conventions. This headword has no recorded confusable partner, since no other headword is close enough in sound or shape to pair with it.

Etymologically, the entry records: From international scientific vocabulary, from German Bilirubin. By surface analysis, bili- + rub- + -in. The German word was naturalized into other languages as international scientific vocabulary (e.g., bilirubin, bilirubine, bilirubina). The correct English form is bilirubin, spelled B-I-L-I-R-U-B-I-N.

Definition

  1. 1
    A bile pigment that is a product of the breakdown of the heme portion of hemoglobin (which occurs within macrophages as they digest red blood cells), and which is responsible for the yellowish color seen in bruises. Extremely high levels of bilirubin may cause jaundice.

Recorded use

Wiktionary example

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

  1. The doctors said this was very common, just her new-born liver catching up with the rest of her — the build-up of bilirubin in her blood. The substance red blood cells produce when broken down.

Etymology

From international scientific vocabulary, from German Bilirubin. By surface analysis, bili- + rub- + -in. The German word was naturalized into other languages as international scientific vocabulary (e.g., bilirubin, bilirubine, bilirubina).

This word in other languages

bilirubine(Français)Bilirubin(Deutsch)bilirrubina(Português)

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 "bilirubin"?
"bilirubin" is spelled B-I-L-I-R-U-B-I-N. The IPA pronunciation is /bɪlɪˈɹuːbɪn/.
What does "bilirubin" mean?
As a noun, "bilirubin" means: A bile pigment that is a product of the breakdown of the heme portion of hemoglobin (which occurs within macrophages as they digest red blood cells), and which is responsible for the yellowish colo...
How do you pronounce "bilirubin"?
The IPA (International Phonetic Alphabet) transcription for "bilirubin" is /bɪlɪˈɹuːbɪn/. 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 "bilirubin"?
From international scientific vocabulary, from German Bilirubin. By surface analysis, bili- + rub- + -in. The German word was naturalized into other languages as international scientific vocabulary (e.g., bilirubin, bilirubine, bilirubina). 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 "bilirubin", not the corpus desk frequency band.

Same letter count

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

billionth#65,731bioenergy#65,732Belgravia#65,726Beelzebub#65,722

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

Source: FrequencyWords open word-frequency list