Immortal means living forever, never dying. In Greek myths, gods like Zeus and Athena were immortal: they could be wounded but would heal and continue living for all eternity. Vampires in stories are often portrayed as immortal creatures who walk the earth century after century.

The opposite of immortal is mortal, which describes anything that will eventually die. Humans, animals, and plants are all mortal. We might call someone a “mere mortal” playfully, meaning they're an ordinary creature bound by the normal rules of life and death.

The word also describes something so memorable or important that it seems like it will last forever. A writer might achieve immortality through a book that people still read hundreds of years later. Shakespeare achieved a kind of immortality because his plays remain popular more than 400 years after his death. Scientists sometimes call certain cells immortal when they can divide and replicate endlessly in laboratory conditions, unlike normal cells that eventually stop dividing.

When something is immortalized, it means it's been preserved or commemorated in a way that will last: a statue immortalizes a historical figure, or a photograph immortalizes a special moment.