mortal (n.) Look up mortal at Dictionary.com
"mortal thing or substance," 1520s, from mortal (adj.). Latin mortalis also was used as a noun, "a man, mortal, human being."
mortal (adj.) Look up mortal at Dictionary.com
mid-14c., "deadly," also "doomed to die," from Old French mortel "destined to die; deserving of death," from Latin mortalis "subject to death, mortal, of a mortal, human," from mors (genitive mortis) "death." This is reconstructed to be from PIE *mr-o- "to die," *mr-to- "dead," *mr-ti- "death," sll from PIE root *mer- "to rub away, harm" (also "to die" and forming words referring to death and to beings subject to death). The most widespread Indo-European root for "to die," it forms the common word for it except in Greek and Germanic.