WordDictionary

Noun:

• A coming to; the act of acceding and becoming joined; as, a king's '''accession''' to a confederacy.
• Increase by something added; that which is added; augmentation from without; as, an '''accession''' of wealth or territory.
• legal 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). Thus, the owner of a cow becomes the owner of her calf.
• legal The act by which one power becomes party to engagements already in force between other powers - Kent
• medicine The invasion, approach, or commencement of a disease; a fit or paroxysm.
• The act of coming to or reaching a throne, an office, or dignity; as, the '''accession''' of the house of Stuart; -- applied especially to the epoch of a new dynasty.

Verb:

• transitive To make a record of (additions to a collection).