/ɪˈmɔːrtəl/
[adjective] Describing someone or something that lives or lasts forever and cannot die or be destroyed. It can also describe something so great or famous that people will never forget it.
The word 'immortal' carries the ghost of death inside it — 'mort', the Latin word for dying, is literally at its heart.
To understand 'immortal', you must first meet its opposite. The Latin word 'mors' meant death — raw, final, unavoidable death. From 'mors' came the adjective 'mortalis', meaning 'subject to death' or 'capable of dying', which described every creature that breathed and bled. The Romans used it constantly, in poetry, philosophy, and law. It was simply the word for what all living things were: mortal. Temporary. Fated to end.
But language, like the human imagination, hungers for escape. Latin formed negatives by attaching the prefix 'im-' (a form of 'in-', meaning 'not') to adjectives. So 'immortalis' was built directly from 'im-' plus 'mortalis', meaning quite literally 'not subject to death'. The gods of the Roman pantheon were 'immortales' — the immortals — beings who existed beyond the reach of time and decay. The word carried enormous weight in Roman religious and philosophical thought, especially in debates about whether the human soul might share in that divine permanence.
The word passed from classical Latin into the literary and ecclesiastical traditions of medieval Europe, carried by scholars, priests, and philosophers who wrote and debated in Latin long after the Roman Empire had fallen. When English writers of the 14th century began reaching for the concept, they borrowed 'immortal' almost whole from Latin 'immortalis', making only the small adjustments needed to fit English speech. The word arrived in English already fully formed, already freighted with centuries of theological and philosophical meaning.
Over time, 'immortal' quietly expanded beyond its original religious sense. While it still described gods and souls that could never die, it began to attach itself to more earthly things — a reputation, a work of art, a name. By the Renaissance and into the 17th and 18th centuries, poets and writers were calling great works or great people 'immortal' not because they would literally live forever, but because their fame seemed to defy ordinary forgetting. Shakespeare's sonnets famously promised to make his subject immortal through verse — a metaphor that has since become entirely ordinary.
The Latin root 'mors' and its adjective 'mortalis' gave English a surprisingly large family of words, each tracing the same path through Latin into English. Latin 'mortalis' became Old French 'mortel', which entered Middle English as 'mortal'. The Latin 'mors' also produced 'mortem', the accusative form, which fed into Old French 'mort' and later gave English words like 'murder' (through Old English 'morthor', itself from a Proto-Germanic root that blended with the Latin influence), 'mortuary', 'mortgage' (literally 'dead pledge', from Old French 'mort' plus 'gage'), and 'mortify' (from Latin 'mortificare', meaning to put to death or humiliate). Even 'post-mortem' and 'rigor mortis' came into English directly from Latin. All of them carry that ancient word for death at their core.
What makes 'immortal' genuinely fascinating is the particular hunger it reveals in human language. Every culture invents a word for living forever, because the idea is too important, too terrifying, and too beautiful to go unnamed. The English word just happens to be built from the Roman gods' own description of themselves — borrowed first by philosophers, then by priests, then by poets, and finally by anyone who has ever wanted to say that something matters too much to disappear.