Adhesion (noun)

1. The process or state of sticking together of two surfaces in contact.
2. A close connection, relationship, or association.
3. A binding contract or agreement, especially in business or law.

Origin:

Mid 17th century: from latin adhaesio(n-), from adhaerere "stick to".

Examples:

1. The adhesion of the two materials was tested in the laboratory.
2. The adhesion between the two surfaces was very strong.
3. The adhesion between the two companies was based on mutual interests.
4. The adhesion was a binding agreement between the two parties.
5. The adhesion was essential for the success of the project.