accession

American  

[ak-sesh-uhn] / ækˈsɛʃ ən /

noun

1. the act of coming into the possession of a right, title, office, etc..

   accession to the throne.

2. an increase by something added.

   an accession of territory.

3. something added.

   a list of accessions to the college library.

4. Law. addition to property by growth or improvement.

5. consent; agreement; approval.

   accession to a demand.

6. International Law. formal acceptance of a treaty, international convention, or other agreement between states.

7. the act of coming near; approach.

8. an attack or onset, as of a disease.

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verb (used with object)

1. to make a record of (a book, painting, etc.) in the order of acquisition.

2. to acquire (a book, painting, etc.), especially for a permanent collection.

accession British  

/ əkˈsɛʃən /

noun

1. the act of entering upon or attaining to an office, right, condition, etc

2. an increase due to an addition

3. an addition, as to a collection

4. property law

   1. an addition to land or property by natural increase or improvement

   2. the owner's right to the increased value of such land

5. international law the formal acceptance of a convention or treaty

6. agreement; consent

7. a less common word for access

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verb

1. (tr) to make a record of (additions to a collection)

Other Word Forms

Derived Forms

• reaccession
  noun
• nonaccession
  noun
• unaccessional
  adjective
• accessional
  adjective

Etymology

Origin of accession

1580–90; < Latin accessiōn- (stem of accessiō ) an approach, addition. See access, -ion

Explanation

Accession is the act of advancing into a position. Being elected class president is a kind of accession. Accession originally referred to a queen or king taking the throne. From the Latin term, accessionem, meaning "joining or increasing,” accession may refer to the gaining of access to any formal position, group, or right. It can also mean “agreement” — think of it as “joining in.” Accession may also refer to property — either something that increases your original collection, or the right to all of your property even through growth — such as the golden egg your new hen laid.

Example Sentences

Since the war began, both Ukraine and Moldova have joined the queue of countries seeking accession alongside the Balkan hopefuls: Albania, Bosnia, Kosovo, North Macedonia, Montenegro and Serbia.

From Barron's • Jun. 5, 2026

Georgian Prime Minister Irakli Kobakhidze said last year that Tbilisi's path towards joining the EU was "steady and irreversible", despite Brussels effectively freezing Georgia's accession process.

From Barron's • May 26, 2026

The Chinese share of U.S. imports has now fallen below where it stood before Beijing’s WTO accession 25 years ago.

From MarketWatch • May 14, 2026

The trip had originally been set for 22 to 26 April, to mark the 40th anniversary of Eswatini's King Mswati III's accession.

From BBC • May 2, 2026

The accession of fortune, the discovery of my relations, followed in due order.

From "Jane Eyre" by Charlotte Brontë

Related Words

• enlargement
• extension