1. The action or fact of ceasing to exist or function.
2. The state of being extinct.
3. Biology: The death of the last individual of a species or other taxonomic group, resulting in the disappearance of that group.
4. Ecology: The functional or practical cessation of a species's existence in a particular ecosystem or locality.
5. Metaphysics: The termination or cessation of something, especially in the sense of its passing out of existence or consciousness.