A more thorough explanation:

Adhesion is a term that refers to the act of sticking or attaching something to another thing. It can also mean the acquisition of a right or office, or the joining of a nation to a treaty. In legal terms, it can refer to the right of a property owner to all that is added to their property, either naturally or by labor.

• A sticker adhering to a piece of paper
• A country joining a treaty through accession
• A homeowner acquiring a newly poured concrete driveway as their property by accession

These examples illustrate how adhesion can refer to physical sticking, joining of nations to treaties, and the acquisition of property rights through labor or natural processes.