Answer:
Definition :
A senior citizen who is 100 years old or older.
In Literature :
Short Trips: The Centenarian is a Big Finish original anthology edited by Ian Farrington and based on the long-running British science fiction television series Doctor Who. The collection follows the life of a man, Edward Grainger, from his birth through to his death and explores the history of the twentieth century. Like all Doctor Who spin-off media, its relationship to the ongoing story of the television series is open to interpretation