Middle English, from Old English woruld, worold "human secular existence, pursuits, pleasures, and worries of this life," also "a long period of time," also "the human race, mankind, humanity" (but not "the earth"), a word peculiar to Germanic languages, with a literal sense of "age of man."

It is reconstructed to be from a Proto-Germanic compound of *wer "man" (Old English wer, still in werewolf; see virile) and *ald "age" (Old English ald; see old). Cognates include Old Saxon werold, Old Frisian warld, Dutch wereld, Old Norse verold, Old High German weralt, German Welt). Latin saeculum can mean both "age" and "world," as can Greek aiōn.

Originally "life on earth, this world (as opposed to the afterlife)." The sense extended to "the known world," then to "the physical world in the broadest sense, creation, the universe" (by c. 1200).

The oldest sense is in world without end (translating Latin saecula saeculorum), and in worldly. In theology especially "that part of humanity devoted to secular affairs and pleasures of the present state" (mid-14c.), a sense often revived by later sects. In modern scientific conception, "planetary body conceived of as peopled," by 1713.