The adsorption of water by the solid particles of an adsorbent causing it to enormously increase in volume without forming a solution is called imbibition. Solid substances or adsorbents which take part in imbibition are called imbibants, e.g., seeds, dry wood. The liquid (usually water) which is imbibed is known as imbibate. The imbibate is held in between and over the surface of particles of the solid substance through the processes of capillarity and adsorption. The swelling imbibant also develops a pressure called imbibition pressure (matric potential).