1670s, "commentary between two choric songs in a Greek tragedy," also "an incidental narrative or digression within a story, poem, etc.," from French épisode or directly from Greek epeisodion "an episode," literally "an addition," noun use of neuter of epeisodios "coming in besides," from epi "in addition" (see epi-) + eisodos "a coming in, entrance" (from PIE root *en "in").
The second element is a compound of eis "into" + hodos "a way, path; a journey; a method, system," a word of uncertain origin (see Exodus). Transferred sense of "outstanding incident, experience" first recorded in English 1773. Transferred by 1930s to individual broadcasts of serial radio programs.
updated on January 14, 2018