Legal Definitions - instrument of accession

An instrument of accession is a formal document that acknowledges a state's consent to an existing treaty. It is exchanged with the treaty parties or deposited with a designated state or international organization. This allows a nation that did not originally sign a treaty to become a party to it.

For example, Italy became a party to the nuclear-arms treaty by accession. This means that Italy agreed to the terms of the treaty even though they did not sign it originally.

Another example of accession is when a property owner has the right to all that is added to their property, including land left by floods and improvements made by others. For instance, if a homeowner has a newly poured concrete driveway, it becomes their property by accession.

Overall, an instrument of accession is an important legal document that allows nations to become parties to existing treaties and for property owners to claim ownership of improvements made to their property.