mononucleosis

/ˌmɑnoʊnukliˈoʊsɪs/

//ˌmɑnoʊnukliˈoʊsɪs// noun

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

"mononucleosis" is a 13-letter English headword indexed on PlainSpell.

The verdict

“mononucleosis” is uncommon English (frequency #92,891 among 4,057 “M” headwords), classed as a noun. The kind of spelling people second-guess.

#92,891
frequency rank, English
4,057
“M” headwords

According to Wiktionary data (CC BY-SA, analyzed September 3, 2026) - A viral infection marked by extreme fatigue, high fever, and swollen lymph nodes.

Corpus desk

Index EN-mononucleosis · mononucleosis · English

mononucleosis · rank #92,891 · 0 variants · 0 confusables

  • FREQ-RARE #92,891
  • LEN-MEGA 13 letters
  • VOW-6 6 vowels
  • CONFUS-0 No pairs
  • VAR-0 0 variants
  • BOOK-MID 4,057
  • PHOTO-FINISH mommie

Nearest frequency peer: mommie (-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 “mononucleosis”

Sparse band: bars invert rank so rarer forms read shorter

corpus weight

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

Source FrequencyWords open word-frequency list As of September 3, 2026
Key facts for mononucleosis
PropertyValue
Headwordmononucleosis
LanguageEnglish
Part of speechNoun
IPA/ˌmɑnoʊnukliˈoʊsɪs/
Letters13
Frequency rank#92,891
Misspellings tracked0
Confusable pairs0
SourceWiktionary (kaikki.org)

Long-tail rank of “mononucleosis” 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).mononucleosisfalls 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: “mommie” (#92,890), “moonbase” (#92,892), “moke” (#92,889). Among 4,057 “M” headwords, “mononucleosis” is #92,891. Source: FrequencyWords open word-frequency list.

Rare enough to double-check

mononucleosis is uncommon English at frequency #92,891 among 4,057 “M” headwords, classed as anoun, transcribed /ˌmɑnoʊnukliˈoʊsɪs/. Rarity is why readers land here mid-draft. Gloss: "A viral infection marked by extreme fatigue, high fever, and swollen lymph nodes.".

mononucleosis has no tracked misspelling variants, since its letter pattern doesn't lend itself to common typo substitutions. This headword has no recorded confusable partner, since its spelling is unusual enough that it doesn't cluster with a lookalike.

Etymologically, the entry records: From mono- + nucleus + -osis. The correct English form is mononucleosis, spelled M-O-N-O-N-U-C-L-E-O-S-I-S.

Definition

  1. 1
    A viral infection marked by extreme fatigue, high fever, and swollen lymph nodes.

Etymology

From mono- + nucleus + -osis.

This word in other languages

mononucleosis(Español)mononucléose(Français)Pfeiffer-Drüsenfieber(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 "mononucleosis"?
"mononucleosis" is spelled M-O-N-O-N-U-C-L-E-O-S-I-S. The IPA pronunciation is /ˌmɑnoʊnukliˈoʊsɪs/.
What does "mononucleosis" mean?
As a noun, "mononucleosis" means: A viral infection marked by extreme fatigue, high fever, and swollen lymph nodes.
How do you pronounce "mononucleosis"?
The IPA (International Phonetic Alphabet) transcription for "mononucleosis" is /ˌmɑnoʊnukliˈoʊsɪs/. 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 "mononucleosis"?
From mono- + nucleus + -osis. 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 "mononucleosis", not the corpus desk frequency band.

Same letter count

Frequency-ranked English headwords with 13 letters (nearest by frequency rank).

oversensitive#92,967poliomyelitis#93,028inquisitorial#92,728inexpressible#92,719

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

Source: FrequencyWords open word-frequency list