Having been formally registered or cataloged, especially upon acquisition into a collection, museum, or library.
From accession as a verb, plus -ed (the past participle suffix). When items are formally added and recorded, they are said to be 'accessioned.'
Every artifact in a major museum is 'accessioned'—meaning it's been assigned a number, photographed, described, and entered into the database—and without this system, museums would lose track of millions of objects!
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