Source : Webster's Revised Unabridged Dictionary (1913)

Episode \Ep"i*sode\, n. [Gr. ? a coming in besides, ? episode; ?
   into, besides + ? a coming in, ? into + ? way, cf. Skr. sad
   to go: cf. F. ['e]pisode.] (Rhet.)
   A separate incident, story, or action, introduced for the
   purpose of giving a greater variety to the events related; an
   incidental narrative, or digression, separable from the main
   subject, but naturally arising from it.

Source : WordNet®

episode
     n 1: a happening that is distinctive in a series of related
          events
     2: a brief section of a literary or dramatic work that forms
        part of a connected series
     3: a part of a broadcast serial [syn: {installment}, {instalment}]
     4: film consisting of a succession of related shots that
        develop a given subject in a movie [syn: {sequence}]