Accession

something added to what you already have

agreeing with or consenting to (often unwillingly)

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

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

the right to enter

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

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