accession
n. countable C1 Advanced US //əkˈsɛʃən// UK //ɐksˈɛʃən// ac·ces·sion
n. the act of joining a group, organization, or country. It can also mean the moment a person becomes king or queen.
n. the action of joining an organization, treaty, or political union; the formal assumption of a throne or office.
The country's accession to the union took years.
Her accession to the throne marked the end of a long royal transition.
The accession of new members to the trade bloc required complex negotiations on tariffs and border controls.
Ultimately from Latin accessiō(n), from accēdō (English accede). Cognate to French accession. First attested in 1646.