What do you mean by hygroscopic water and l combined water in the soil? Are these available to plants?

Hygroscopic means tendency of absorbing moisture from the air. Some water in the soil forms an extremely thin tightly held film around the soil particles. It is called hygroscopic water. In the soil, a small portion of soil water is chemically bound with soil materials. It is called combined water. Both of these types of water in the soil are not available to plants for absorption by their roots.