Bound water refers to water molecules that are closely associated with other molecules or structures, such as proteins, carbohydrates, or cell membranes, in such a way that they are not free to move or participate in chemical reactions like free water molecules. This type of water is typically found in biological tissues, food products, and other materials where water is held tightly by hydrogen bonds or other forms of interaction. Bound water does not freeze at the normal freezing point of water and has distinct physical and chemical properties compared to free or bulk water.