That sounds like an interesting eggcorn that I haven't heard before, probably derived from "death knell" with echos of "another nail in the coffin". I see that

That sounds like an interesting eggcorn that I haven't heard before, probably derived from "death knell" with echos of "another nail in the coffin". I see that it's been already discussed at the Eggcorn Database forum: http://eggcorns.lascribe.net/forum/viewtopic.php?id=1195 http://eggcorns.lascribe.net/forum/viewtopic.php?id=1195 so it's at least somewhat common For reference, an eggcorn is this: http://en.wikipedia.org/wiki/Eggcorn http://en.wikipedia.org/wiki/Eggcorn