addendum

/əˈdɛn.dəm/

//əˈdɛn.dəm// noun

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

"addendum" is a 8-letter English headword indexed on PlainSpell.

The verdict

“addendum” has 10 generated spelling variants in the English index at frequency #33,106. The variants make it a useful spelling check.

#33,106
frequency rank, English
3,931
“A” headwords
10
tracked misspellings

According to Wiktionary data (CC BY-SA, analyzed September 3, 2026) - Something to be added; especially text added as an appendix or supplement to a document.

Corpus desk

Index EN-addendum · addendum · English

addendum · rank #33,106 · 10 variants · 0 confusables

  • FREQ-MID #33,106
  • LEN-LONG 8 letters
  • VOW-3 3 vowels
  • CONFUS-0 No pairs
  • VAR-MID 10 variants
  • BOOK-MID 3,931
  • PHOTO-FINISH acme

Nearest frequency peer: acme (-2 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.

Rank peers near misspelling magnet “addendum”

Same rarity band: useful when a typo lands on a peer headword

corpus weight

What this shows “addendum” sits among these FrequencyWords peers; misspelling depth is tracked separately in the edit-distance chart.

Source FrequencyWords open word-frequency list As of September 3, 2026
Key facts for addendum
PropertyValue
Headwordaddendum
LanguageEnglish
Part of speechNoun
IPA/əˈdɛn.dəm/
Letters8
Frequency rank#33,106
Misspellings tracked10
Confusable pairs0
SourceWiktionary (kaikki.org)

Frequency seat of misspelling magnet “addendum”

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).addendumlands here:

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

Scale is logarithmic (each tick is 10× rarer). Same rarity band neighbours include “acme” (#33,104), “adsorption” (#33,108), “abnormality” (#33,103). Among 3,931 “A” headwords, “addendum” is #33,106. Source: FrequencyWords open word-frequency list.

A misspelling magnet

The generator records 10 spelling variants around addendum (IPA /əˈdɛn.dəm/), anoun. Corpus frequency is #33,106 among 3,931 “A” headwords. Wiktionary lists 3 senses, so context still picks the gloss.

Our generated misspelling index lists 10 likely wrong-spelling variants for addendum, with forms such as "addednum", "addenddum", and "addendmu". Each of these forms differs from the correct spelling by one small edit: a doubled letter, a dropped silent letter, or a substituted vowel. This entry stands alone in our confusable dataset, a sign it's visually distinctive enough not to be mixed up with another word.

Etymologically, the entry records: From the gerundive of Latin addere (“to add”). The correct English form is addendum, spelled A-D-D-E-N-D-U-M.

Definition

  1. 1
    Something to be added; especially text added as an appendix or supplement to a document.
  2. 2
    A postscript.
  3. 3
    The height by which the tooth of a gear projects beyond (outside for external, or inside for internal) the standard pitch circle or pitch line.

Recorded use

Wiktionary examples

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

  1. An addendum was added to the contract to clarify payment terms.
  2. The author included an addendum at the end of the book.

Etymology

From the gerundive of Latin addere (“to add”).

This word in other languages

adenda(Español)addendum(Français)Anhang(Deutsch)

Common misspellings

Also misspelled as:

  • addednum
  • addenddum
  • addendmu
  • addendumm
  • addenndum
  • addenudm
  • addnedum
  • adedndum
  • adendum
  • dadendum

Misspelling Pattern Breakdown

How far each generated variant is from the correct spelling of addendum - counted as single-character edits (an insertion, a deletion, or a substituted letter). The larger the bar, the easier the typo is to spot; one-edit slips are the ones that sneak past readers.

addednum2addenddum1addendmu2addendumm1addenndum1addenudm2addnedum2adedndum2
Edit distance from "addendum"

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 "addendum"?
"addendum" is spelled A-D-D-E-N-D-U-M. The IPA pronunciation is /əˈdɛn.dəm/.
What does "addendum" mean?
As a noun, "addendum" means: Something to be added; especially text added as an appendix or supplement to a document.
What are common misspellings of "addendum"?
Common misspellings include "addednum", "addenddum", "addendmu", "addendumm", "addenndum". The correct spelling is "addendum".
How do you pronounce "addendum"?
The IPA (International Phonetic Alphabet) transcription for "addendum" is /əˈdɛn.dəm/. 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 "addendum"?
From the gerundive of Latin addere (“to add”). 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 "addendum", not the corpus desk frequency band.

Same letter count

Frequency-ranked English headwords with 8 letters (nearest by frequency rank).

amenable#33,117woodruff#33,094Woodford#33,093Woodbury#33,092

Similar misspelling depth

Headwords with a similar count of attested misspellings (10 here; floor ≥5).

villager10 variantsBalmain10 variantsbarcode10 variantsBianchi10 variants

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

Source: FrequencyWords open word-frequency list