Definitions for "Filk"
Keywords:  parody, lyric, song, folksong, fannish
A fannish folksong, often a parody of standard folksongs. Also: filksong. (2) A filksong festival. Also filkfest. (3) filk: To sing filksongs. Also: filksinging.
Sounds dirty, but this simply refers to a parody or rewriting of a song to cater to a specific fandom. It also refers to any original song written about or within a particular fandom.
a new lyric set to an existing tune
v.i. To engage in rampant and offensive copyright infringement.