The term "hydrophobic" refers to substances that do not mix well with water. These materials tend to repel water molecules, making them resistant to wetting. Common examples of hydrophobic substances include oils and fats, which do not dissolve in water and often form separate layers when combined. In scientific contexts, hydrophobic properties are important in various fields, including biology and chemistry. For instance, the structure of cell membranes is largely hydrophobic, allowing cells to maintain their internal environment. Understanding hydrophobic interactions helps in the development of water-repellent coatings and in studying protein folding.