n. & v.
n. 1 entering upon an office (esp. the throne) or a condition (as manhood). 2 (often foll. by to) a thing added (e.g. a book to a library); increase, addition. 3 Law the incorporation of one item of property in another. 4 assent; the formal acceptance of a treaty etc.
v.tr. record the addition of (a new item) to a library or museum.
[ F accession or L accessio -onis (as ACCEDE) ]