An Etymological Dictionary of Astronomy and Astrophysics

1. An incident in the course of a series of events.
   

2. An incident, scene, etc., within a narrative, usually fully developed and either integrated within the main story or digressing from it (Dictionary.com).

Etymology (EN): From Fr. épisode from Gk. epeisodion “addition,” noun use of neuter of epeisodios “coming in besides,” from → epi- “in addition” + eisodos “a coming in, entrance” (from eis“into” + hodos “way,” → period).

Etymology (PE): Apyâ, literally “coming in besides,” from api-, → epi-,

• â- present stem of âmadan “to come,” → rise.