Meaning

originOriginally "filk music" was a typo for "folk music" in a never-published essay on the influence of Science Fiction and Fantasy on folk music. Its first known deliberate use was by Karen Kruse Anderson in Die Zeitschrift für Vollständigen Unsinn (The Journal for Utter Nonsense) #774 (June 1953), for a song written by science-fiction author Poul Anderson.

Etymology from Wiktionary, CC BY-SA 3.0