Meaning of running joke

run'ning joke'

Pronunciation: [key]
  1. a joke or humorous allusion used recurrently in a play, film, television skit, etc., for a cumulative comic effect.
  2. a subject, reference, remark, etc., that is a continual source of humor. Also called
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.