What is the X in X-mas?
An imaginary family consisting of Fred and Mary Bloggs and their children. Used as a standard example in knowledge representation to show the difference between extensional and intensional objects. For example, every occurrence of "Fred Bloggs" is the same unique person, whereas occurrences of "person" may refer to different people. Members of the Bloggs family have been known to pop up in bizarre places such as the DEC Telephone Directory. Compare Mbogo, Dr. Fred.