terrestrial tuh-RES-tree-uhl\ (adjective) - 1 : Pertaining to the earth or its inhabitants. 2 : Pertaining to the land (as distinct from water or air) or those living on land. 3 : Worldly, mundane. (noun) - One living on the earth.
"Suddenly, Jeff remembered that an anniversary of extraordinary terrestrial significance, the explosion of the island of Krakatoa, had been completely overlooked."
From Latin terrestris (relating to earth), from terra (earth). Some other words derived from the same Latin root are terrace, mediterranean, turmeric, country, subterranean, territory, terrier, and terra cotta.