Accession
/æk.ˈsɛ.ʃən/
noun
A coming to; the act of acceding and becoming joined
“a king's accession to a confederacy”
Increase by something added; that which is added; augmentation from without.
A mode of acquiring property, by which the owner of a corporeal substance which receives an addition by growth, or by labor, has a right to the part or thing added, or the improvement (provided the thing is not changed into a different species).
verb
To make a record of (additions to a collection).