accession - noun

a process of increasing by addition (as to a collection or group)

(civil law) the right to all of that which your property produces whether by growth or improvement

something added to what you already have

agreeing with or consenting to (often unwillingly)

the right to enter

the act of attaining or gaining access to a new office or right or position (especially the throne)

accession - verb

• make a record of additions to a collection, such as a library

accession - thesaurus

access   addition   admission   admittance   assenting   entree