A more thorough explanation:

Definition: Extinct, adjective, means that something no longer exists or is in use. It can also refer to a debt that has no claimant.

• The dinosaurs are extinct, which means they no longer exist on Earth.
• The typewriter is an extinct technology, as it is no longer commonly used.
• That debt is extinct because the person who owed the money has passed away and has no heirs to claim it.

The examples illustrate the definition of extinct by showing things that are no longer in existence or use. The first example shows how the dinosaurs are extinct and no longer exist on Earth. The second example shows how the typewriter is an extinct technology because it is no longer commonly used. The third example shows how a debt can be extinct if there is no one to claim it.