What is the meaning of accession?

noun

• A process of increasing by addition (as to a collection or group. )
  • usage: "the art collection grew through accession"
• Civil law. ( the right to all of that which your property produces whether by growth or improvement)
• Something added to what you already have.
  • usage: "the librarian shelved the new accessions"; "he was a new addition to the staff"
  • synonyms: addition
• Agreeing with or consenting to (often unwillingly. )
  • usage: "accession to such demands would set a dangerous precedent"; "assenting to the Congressional determination"
  • synonyms: assenting
• The right to enter.
  • synonyms: entree, access, admission, admittance
• The act of attaining or gaining access to a new office or right or position (especially the throne. )
  • usage: "Elizabeth's accession in 1558"
  • synonyms: rise to power

verb

• Make a record of additions to a collection, such as a library. .