Adhesion is the tendency of dissimilar particles or surfaces to cling to one another (cohesion refers to the tendency of similar or identical particles/surfaces to cling to one another).

IUPAC definition

Process of attachment of a substance to the surface of another substance.

Note 1: Adhesion requires energy that can come from chemical and/or physical
linkages, the latter being reversible when enough energy is applied.

Note 2: In biology, adhesion reflects the behavior of cells shortly after contact
to the surface.

Note 3: In surgery, adhesion is used when two tissues fuse unexpectedly.[1]

The forces that cause adhesion and cohesion can be divided into several types. The intermolecular forces responsible for the function of various kinds of stickers and sticky tape fall into the categories of chemical adhesion, dispersive adhesion, and diffusive adhesion. In addition to the cumulative magnitudes of these intermolecular forces, there are also certain emergent mechanical effects.