Cohesion
Cohesion, the force of attraction that holds the molecules of a substance together. The strength of this force depends upon the physical state of the substance. It is greatest for solids, in which molecules are close together. In liquids, the molecules are farther apart and the force is less. Cohesion is least in gases, the molecules being so widely spaced that a gas can occupy any shape or volume.
Sometimes there is a strong attraction between molecules of unlike substances in contact, as between wood and glue. This force, which is distinct from cohesion, is called adhesion.