A term, phrase, or pun that is
funny to you when you say it, but not
funny to anybody else. Then when somebody else says it, it is
funny to them but no longer funny to you.
(pointing to a billboard advertising a
bill-managing service) "Look at that
BILL-board. hahaha" nobody else laughs.
Later, somebody else says "Look at that
BILL-board, hahaha" and again, nobody else laughs not even the original joker.
This situation is a keyosk.