A short description of filk, and links to definitions and other filk events, can be found here.

12-Tone Technique bases the melodies and harmonies of a piece
on an ordering of the 12 notes of the chromatic scale.
The 12 tones of an octave are not centered around any single tone,
but are united by the composer's selected order of tones for a given composition.
This technique represented a clear break with the harmonic formulas of music
that had been developed during the 18th and 19th centuries.