Euryhalin refers to organisms that can tolerate a wide range of salinity levels in their environment. This adaptability allows them to thrive in various aquatic habitats, from freshwater to brackish and saltwater. Examples of euryhaline species include certain fish, crustaceans, and amphibians that can survive fluctuations in salinity. Their physiological mechanisms enable them to regulate osmotic pressure effectively, making them resilient to changes in their surroundings.