An Etymological Dictionary of Astronomy and Astrophysics
English-French-Persian

1) The act or state of adhering; state of being adhered or united.
2) Steady or devoted attachment, support, etc.; adherence.
3) Physics: The molecular force of attraction in the area of contact between unlike bodies that acts to hold them together (Dictionary.com). See also → cohesion.

Verbal noun from → adhere; → -tion.