accession(redirected from accessioned)
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2. In international relations, the process by which a country joins the European Union.
3. See: Acquisition.
The right to own things that become a part of something you already own.When a tenant adds built-in cabinetry or other fixtures to a building,they become the property of the landlord by virtue of accession. Also frequently encountered in the realm of riparian (water) rights, such as new land created by dry river beds or retreating tidal lands.