To mutate means to change in form or structure, especially in ways that create something noticeably different from the original. The word most commonly describes changes in living things at the genetic level. When an organism's DNA mutates, it can develop new traits that weren't present in its parents.

Mutations happen constantly in nature and drive evolution. A butterfly might mutate to have slightly different wing patterns. Bacteria mutate rapidly, which is why doctors worry about diseases becoming resistant to medicine. Most mutations are tiny and go unnoticed, but occasionally one creates a significant advantage: perhaps a plant mutates to survive drought better, or a bird develops a beak shape that helps it crack tough seeds.

In science fiction, the word often describes dramatic transformations: a character gets exposed to radiation and mutates into something completely different. Real mutations work more subtly, accumulating small changes over many generations rather than creating instant transformations.

The word can also describe non-biological changes. A simple game might mutate over time as kids add new rules. A melody mutates when a composer experiments with variations. When something mutates, it keeps its basic identity but develops new characteristics that set it apart from where it started.