Emily Dickinson Lexicon

AC-CESS'ION, n. [L. accessio.]

1. A coming to; an acceding to and joining; as, a king's accession to a confederacy.
2. Increase by something added; that which is added; with invitation; as an accession of wealth or territory.
3. In late, 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 thing added or improvement; provided the thing is not changed into a different species. Thus the owner of a cow becomes to owner of her calf. – Blackstone.
4. The act of arriving at a throne, an office, or dignity.
5. That which is added. The only accession which the Roman Empire received, as the province of Britain. – Gibbon.
6. The invasion of a fit of a periodical disease, or fever. It differs from exacerbation. Accession implies a total previous intermission, as of a fever; exacerbation implies only a previous remission or abatement of violence.