A lot of what I said in my evaporated post seemed self-evident but Mark's original question does hit home. Mark's song "Bowling" is clearly a comical parody in form and tune of the traditional sea shanty "Roll the Woodpile Down" but what would we call that song if the bowling leagues used it at their parties?

If we're simply using the form and tune of an existing song for an entirely new song, we are "adopting" its form and tune, or "stealing it" if we're doing so without the permission of the composer.

If we're altering the form or tune of an existing song, we're "adapting" its form or tune into a new song, or maybe into another version of the same song. It's really not a parody unless it is a comment on the original song.

Now I'm less sure what to call the creation when the new song is a serious version of a comic song, unless it's a malody!

Cheerily,
Charley Noble