When a capillary tube with a fine bore is dipped in water, water rises in the capillary. The extent to which water rises depends on the diameter of the capillary. The smaller the diameter of the capillary, the higher will be the rise of water in the capillary tube.
This property of rise of water inside a capillary is called capillarity or capillary action.
This is the property, by which water from the soil enters the leaves and branches of the plants through the stems.
When a piece of cloth or blotting paper is placed in water, it soaks the water by this process of capillary action. The thread strands in the cloth and cellulose of the blotting paper serves like very fine capillaries for the water to rise.