accession
ac•ces•sionBrE /ækˈseʃn/
NAmE /ækˈseʃn/
noun
word origin1 [uncountable] ~ (to sth) the act of becoming a ruler of a country
example bank
the accession of Queen Victoria to the throne 
see also accede 2 [uncountable] ~ (to sth) the act of becoming part of an international organizationthe accession of new member states to the EU in 2004the new accession states of the EU 3 [countable] (technical) a thing that is added to a collection of objects, paintings, etc. in a library or museum
