Hydrogel is a water-absorbent material made from polymers that can hold large amounts of water while maintaining their structure. These gels are often used in various applications, including medical devices, wound dressings, and agriculture, due to their ability to provide moisture and support healing. The unique properties of hydrogels allow them to swell and retain water, making them useful in products like contact lenses and diapers. They can also be engineered to respond to environmental changes, such as temperature or pH, which enhances their versatility in fields like drug delivery and tissue engineering.