A plant that grows in water is referred to as an "aquatic plant." These plants are adapted to living in or near water bodies, such as lakes, rivers, and wetlands. They can be submersed, floating, or rooted in the water. Aquatic plants play a crucial role in their ecosystems, providing oxygen, food, and habitat for various aquatic organisms. Examples include water lilies, cattails, and duckweed, which display different adaptations to thrive in their watery environments.