accession

noun

1 the Queen's accession to the throne:

succession, elevation;

assumption of, attainment of, inheritance of.

2 the accession of Spain and Portugal to the EC:

joining, signing up, enrollment.

3 accession to the Treaty of Rome was effected in 1971:

assent, consent, agreement;

acceptance of, acquiescence in, endorsement of, compliance with, concurrence with, recognition of.

4 among recent accessions to the museum are some Victorian watercolors:

addition, acquisition, new item, gift, purchase, adjunct, add-on, gain.