cohesion co·he·sion (kō-hē'zhən)
The intermolecular attraction that holds molecules and masses together.
The force of attraction that holds molecules of a given substance together. It is strongest in solids, less strong in liquids, and least strong in gases. Cohesion of molecules causes drops to form in liquids (as when liquid mercury is poured on a piece of glass), and causes condensing water vapor to form the droplets that make clouds. Compare adhesion.