- 1[uncountable] accession (to something) the act of becoming a ruler of a country the accession of the queen to the throne see accede
- 2[uncountable] accession (to something) the act of becoming part of an international organization the accession of new member states to the EU in 2004
- 3[countable] (technology) a thing that is added to a collection of objects, paintings, etc. in a library or museum
Check pronunciation: accession