The word 永垂不朽 is formed by sequentially combining the characters 永 (meaning "forever"), 垂 (meaning "to pass down" or "to bequeath"), 不 (meaning "not"), and 朽 (meaning "to decay" or "to rot"), resulting in a literal composition that conveys "forever passed down without decay", used to express that a person's memory or achievements will last eternally without fading.