accession

(noun) a process of increasing by addition (as to a collection or group). Example: "The art collection grew through accession."

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

(noun) something added to what you already have. Synonyms: addition. Examples: "The librarian shelved the new accessions." "He was a new addition to the staff."

(noun) agreeing with or consenting to (often unwillingly). Synonyms: assenting. Examples: "Accession to such demands would set a dangerous precedent." "Assenting to the congressional determination."

(noun) the right to enter. Synonyms: entree, access, admission, admittance.

(noun) the act of attaining or gaining access to a new office or right or position (especially the throne). Synonyms: rise to power. Example: "Elizabeth's accession in 1558."

(verb) make a record of additions to a collection, such as a library.