blood serum

noun

"blood-serum" is a 10-letter English headword indexed on PlainSpell.

The verdict

“blood serum” is uncommon English (outside the top frequency list), classed as a noun. The kind of spelling people second-guess.

Unranked
below top-frequency English
11
letters

According to Wiktionary data (CC BY-SA, analyzed September 3, 2026) - The portion of whole blood that is not blood cells and not clotting factors; it can be separated as a clear yellowish liquid after the blood has been allowed to clot.

Corpus desk

Index EN-blood-serum · blood serum · English

blood serum · unranked · 0 variants · 0 confusables

  • FREQ-UNRANKED Unranked
  • LEN-MEGA 11 letters
  • VOW-4 4 vowels
  • CONFUS-0 No pairs
  • VAR-0 0 variants
  • BOOK-THIN "B" thin
  • PHOTO-UNK Peer pending

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.

Key facts for blood serum
PropertyValue
Headwordblood serum
LanguageEnglish
Part of speechNoun
Letters11
Misspellings tracked0
Confusable pairs0
SourceWiktionary (kaikki.org)

Long-tail rank of “blood serum” in English

blood serumfalls outside the top-100,000 ranked English words, the long-tail zone of technical, archaic, or low-frequency vocabulary, exactly where readers second-guess spellings most.

Beyond rank #100,000. Source: FrequencyWords open word-frequency list.

Rare enough to double-check

blood serum is uncommon English outside the top frequency list, classed as anoun. Rarity is why readers land here mid-draft. Gloss: "The portion of whole blood that is not blood cells and not clotting factors; it can be separated as a clear yellowish liquid after the blood has been allowed to clot.".

The misspelling generator found no plausible variants for blood serum, suggesting the orthography follows predictable English patterns. Our confusable-pair dataset has no match for it, which typically means the spelling is too distinctive to be mistaken for another word.

Wiktionary doesn't record an etymology for this headword, so its spelling is easiest explained by how it's pronounced rather than where it came from. The correct English form is blood serum, spelled B-L-O-O-D- -S-E-R-U-M.

Definition

  1. 1
    The portion of whole blood that is not blood cells and not clotting factors; it can be separated as a clear yellowish liquid after the blood has been allowed to clot.

Recorded use

Wiktionary example

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

  1. Holonyms: plasma, blood plasma < blood

Definitions, pronunciation, and etymology for this entry are drawn from Wiktionary via the kaikki.org structured extract (CC BY-SA). See the methodology for how each field is sourced and updated.

Frequently Asked Questions

How do you spell "blood serum"?
"blood serum" is spelled B-L-O-O-D- -S-E-R-U-M.
What does "blood serum" mean?
As a noun, "blood serum" means: The portion of whole blood that is not blood cells and not clotting factors; it can be separated as a clear yellowish liquid after the blood has been allowed to clot.
What language does "blood serum" come from?
"blood serum" is a English word. PlainSpell's reference spans five languages -- English, Spanish, Portuguese, French, and German -- with definitions, pronunciations, and spelling data for each.
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.

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

Source: FrequencyWords open word-frequency list