Annexation

[Britney]

The act of annexing; process of attaching, adding,
or appending; the act of connecting; union; as, the annexation of Texas
to the United States, or of chattels to the freehold.

[Lanell]

possession taken of a piece of land or a country, usually by force or without permission:

[Marquetta]

The action of annexing something, especially territory.