From Longman Dictionary of Contemporary Englishaccessionac‧ces‧sion /əkˈseʃən/ noun 1 [uncountable]PGO an official process in which someone becomes king, queen, president etc → successionaccession of the accession of James Iaccession to power/to the throne (=the act of becoming king, queen, president etc)2 [uncountable] formalAGREE the act of agreeing to a demand3 AV[countable] technical an object or work of art that is added to a collection of objects or paintings
Examples from the Corpus
accession• He adds that the line between accession and adhesion is poorly defined.• Aldfrith appears to have been very much on the periphery of Northumbrian dynastic life before his accession.• But in the circumstances of 1483 an immediate accession may have seemed to offer real advantages.• A general right of accession would have created a major inroad into the continuing bilateralism of even multilateral treaties.• Edward II's accession later that year accelerated his rise. 