Word Origin & History
mortalmid-14c., "deadly," also "doomed to die," from O.Fr. mortel "destined to die," from L. mortalis "subject to death," from mors (gen. mortis) "death," from PIE base *mor-/*mr- "die" (cf. Skt. mrtih "death," Avestan miryeite "dies," O.Pers. martiya- "man," Armenian meranim "die," Lith. mirtis "mortal man,"
Gk. brotos "mortal" (hence ambrotos "immortal"), O.C.S. mrutvu "dead," O.Ir. marb, Welsh marw "died," O.E. morþ "murder"). The most widespread IE root for "to die," forming the common word for it except in Gk. and Gmc. The noun meaning "mortal thing or substance" is first recorded 1520s. Related: Mortally.