What does extinction mean?

Living things

Extinct means there are no living members of the species. For example, the dodo bird is extinct. Dodo birds are extinct because they have all been killed and there are none left to continue the species.

Species can become extinct naturally, or by the action of a new or introduced species, or by human activities such as loss of habitat or over hunting.

Geology

A volcano that is not expected to erupt again can be called "extinct" as opposed to "dormant" meaning that it could possibly erupt again.
like animals after a while it goes extinct which means no more species of that kind and will not come again for that species
The definition of extinct is the end of an organism or group of organisms, normally a species.