In popular cultures, "Extraterrestrials" are life forms — especially intelligent life forms— that are of extraterrestrial origin (often also called "aliens").
Famous quotes containing the word life:
“Unto a life which I call natural I would gladly follow even a will-o’-the-wisp through bogs and sloughs unimaginable, but no moon nor firefly has shown me the causeway to it.”
—Henry David Thoreau (1817–1862)