the act of coming into the possession of a right, title, office, etc.

accession to the throne.

an increase by something added

an accession of territory.

something added

a list of accessions to the college library.

Law . addition to property by growth or improvement.

consent; agreement; approval

accession to a demand.

International Law . formal acceptance of a treaty, international convention, or other agreement between states.

the act of coming near; approach.

an attack or onset, as of a disease.

to make a record of (a book, painting, etc.) in the order of acquisition.

to acquire (a book, painting, etc.), esp. for a permanent collection.

noun

decline , fall , disagreement , dispute , repudiation

noun

accretion , addition , augmentation , enlargement , extension , increase , increment , raise , rise , assumption , attainment , inauguration , induction , investment , succession , taking on , taking over , accedence , acceptance , acquiescence , assent , concurrence , consent , acquisition , agreement , approach , arrival , inaugural , installation