The Meaning of Addendum: What It Is and How To Use It

What does the word addendum mean and how can it be used in different fields? This article tells you the many meanings of addendum.

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Have you ever heard the word addendum and wondered what it meant? This article will cover the numerous meanings of addendum depending on the circumstance it is used in, as well as the origin of the word addendum, translations of addendum, and synonyms and antonyms of addendum.

 Keep reading to learn how to use the word addendum yourself!

What Does the Word Addendum Mean?

According to Collins English Dictionary, the word addendum has multiple meanings. This noun generally refers to something that is added to something else. Often, this refers to an addition at the end of a contract, book, or another document. Addendum is three syllables (a-den-dum), and the pronunciation of addendum is əˈdɛndəm

The plural form of addendum is addenda (-). Like many Latin words, this plural form is created by replacing the “dum” in addendum with “da.” This formation is also used with words like alumni and alumnus. 

The word addendum can also refer to a type of radial distance. This distance can either be on an external screw thread between the pitch cylinders of an external screw thread and the major, or it can be the distance between the ridges in the standard pitch circle of a cogwheel or worm wheel and the tip of a gear tooth.

Addenda in Real Estate

According to Investopedia, the word addendum is often used in real estate transactions. Whether it is a lease agreement or a purchase agreement, an addendum will modify the original contract or standard contracts that are used as a template. Addenda are used to eliminate confusion and modify a standardized form or existing contract that a mortgage lender might use. 

An addendum can be used to create responsibilities for the buyer or the seller when it comes to the transaction, with regard to things like the inspection contingencies, disclosures like a property condition disclosure, the schedules of the delivery of goods, if appliances are included in the sale, and other contractual obligations in specific detail. 

A lease addendum might be used by a landlord to adjust the length of the lease by the tenant on the premises. Overall, addenda are used as contract amendments and are a separate document that is attached to the initial contract. This modifies different terms of the contract.

What Is the Origin of Addendum?

According to Dictionary, the term addendum has been used since the 18th century Middle English and comes directly from Latin. The word addendum comes from the Latin word addendus, which means “to be added.” The Latin word addendus is the neuter gerundive of addere, a Latin verb that means “to add.”

What Are Translations of Addendum?

Why might it be useful to know translations of the word addendum into different languages? If you are working on an international contract or if you are communicating with a person who does not speak English about contracts and additions, studying this list of translations of the word addendum can help you communicate.

  • Hindi: परिशिष्ट
  • Norwegian: Addendum
  • Indonesian: tambahan
  • Telugu: అనుబంధ సంస్థ
  • Greek: προσθήκη
  • Basque: adondo
  • Gujarati: ઉમેરો
  • Russian: приложение
  • Korean: 부록
  • Italian: addenda
  • Spanish: apéndice
  • Latvian: papildinājums
  • Turkish: ilave
  • Japanese: 補遺
  • Malayalam: കൂട്ടിച്ചേർക്കൽ
  • German: Nachtrag
  • French: Addenda
  • Estonian: lisand
  • Czech: dodatek
  • Polish: uzupełnienie
  • Portuguese (Brazil): termo aditivo
  • Slovak: dodatok
  • Serbian: додатак
  • Arabic: إضافة
  • Vietnamese: Phụ lục.
  • Ukrainian: додаток
  • Hungarian: függelék
  • Chinese (Taiwan): 附錄
  • Swedish: tillägg
  • Welsh: adendwm
  • Slovenian: Dodatek
  • Chinese (PRC): 附录
  • Amharic: addendum
  • Icelandic: viðbót.
  • Portuguese (Portugal): termo aditivo
  • Thai: ภาคผนวก
  • Catalan: addendum
  • Dutch: addendum
  • Kannada: ಸೇರಿಸು
  • Finnish: lisäys
  • Croatian: dodatak
  • Bulgarian: Допълнение
  • Hebrew: תוֹסֶפֶת
  • Marathi: indendum
  • Bengali: অ্যাডেন্ডাম

What Are Synonyms of the Word Addendum?

The word addendum is often used regarding contracts and business. If you use this word in a situation where business and contracts are not the focus of the conversation, it might confuse people. 

In settings where addendum might not be the perfect word to use, you can try one of the below synonyms of addendum from Power Thesaurus. Any one of these words can be used in specific settings to refer to an addition or additive piece at the end of something. 

  • accession
  • accessory
  • accompaniment
  • accretion
  • add-on
  • addition
  • additions
  • additive
  • adjunct
  • afterthought
  • afterword
  • amendment
  • annex
  • appendage
  • appendages
  • appendices
  • appendix
  • appendixes
  • appurtenance
  • attachment
  • augmentation
  • back matter
  • coda
  • codicil
  • complement
  • continuation
  • epilogue
  • extension
  • extra
  • gain
  • increase
  • increment
  • p.s.
  • postlude
  • postscript
  • postscripts
  • rider
  • sequel
  • supplement
  • supplementation
  • supplements
  • tailpiece

What Are Antonyms of the Word Addendum?

While an addendum refers to an addition, there are also numerous words that can refer to a reduction or a subtraction. Any of the below antonyms of addendum from Power Thesaurus can be used to refer to a reduction or diminishing of something. How many of these antonyms of addendum are you familiar with?

  • abatement
  • abbreviation
  • abridgement
  • alleviation
  • allowance
  • collapse
  • condensation
  • contract
  • contraction
  • curtailment
  • cut
  • cutback
  • cutting
  • decline
  • declining
  • decrease
  • decreasing
  • deduction
  • degradation
  • demotion
  • depreciation
  • deterioration
  • devaluation
  • diminution
  • discount
  • downsizing
  • downturn
  • drawdown
  • drop
  • easing
  • fall
  • falling off
  • lessening
  • limit
  • loss
  • lowering
  • markdown
  • mitigation
  • moderation
  • rebate
  • reduction
  • relief
  • restraint
  • shrinking
  • slackening
  • slump


The word addendum simply refers to an addition. This is often used at the end of a book or other document to refer to some sort of addition and is commonly used in contracts and real estate to refer to modifications to an original contract. The word addendum is a noun, and the plural form of the word addendum is addenda.


  1. Addendum definition and meaning | Collins English Dictionary
  2. Addendum synonyms – 397 Words and Phrases for Addendum | Power Thesaurus  
  3. Addendum | Dictionary 
  4. Reduction synonyms – 1 251 Words and Phrases for Reduction | Power Thesaurus 
  5. Addendum Definition | Investopedia