accession

ot noun

1. A coming to; the act of acceding and becoming joined a king's accession to a confederacy
2. Increase by something added; that which is added; augmentation from without.
3. 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).
4. The act by which one power becomes party to engagements already in force between other powers.

fe’l verb

1. To make a record of (additions to a collection).