"Terrestrial" refers to anything related to the Earth or land. It is often used to describe environments, ecosystems, or organisms that exist on solid ground, as opposed to aquatic or aerial settings. For example, terrestrial plants are those that grow on land, while terrestrial animals are species that live primarily on the ground, such as mammals, birds, and insects. In a broader context, "terrestrial" can also pertain to the study of Earth sciences, which includes disciplines like geology and ecology. This term helps differentiate between various habitats and life forms, emphasizing the importance of land-based ecosystems in the overall balance of nature.