Someone just asked me in chat what a missed note in music is called. Without hesitation, I replied, "A clam." It's what I've always heard in academic and professional settings since forever.
Only now, having to explain its usage and origin, I went looking and found only informal origins and folk-etymology explanations. One such was the notion that it is derived from the expression "to clam up," meaning to fall silent (see Etymonline, which attests it as American from 1916 while noting that the word clam itself has been used as an interjection meaning ‘clam up’ since the 14th century). But there are problems with that. For one thing, a "clam" note is one that is played instead of the actually written or appropriate note. In other words, it sounds ... something that is the opposite of silence.
Here's another attempt at explaining the origin:
The origin of using the word "clam" to describe a missed note is rooted in
the theatre TTBOMK. As I understand it, actors would describe an untimely entrance or forgotten line as "making a clam." Certainly, if that was the case, horn players in the pit would have readily taken up the use of the word and spread it around the musical community.
The "TTBOMK" gives it away as folk etymology, and the argument that follows is what I will charitably call less than rigorous.
Still, it does demonstrate that I'm not the only one who's ever heard the term. And really, almost everywhere I've ever played music the term has come up (though not about my playing—honest!). It's also not the only term used for a missed note (one I especially loved was "approximatura," which played nicely off the musical term appogiatura, but that's a story for another day).
And The Word Detective says:
The likening of a closed mouth, or the human mouth in general, to the bivalve sort of “clam” may underlie the use of “clam” to mean a missed or flubbed note, especially if the term originated in connection with wind instruments. This usage dates back to at least the early 1950s and since then has been applied to an error in any sort of musical or theatrical performance (“Bing Crosby … always said, ‘Leave the clams in, let ’em know I’m human,'” New York Times, 1991). Perhaps the “error” sense of the term lies in the failure of one’s “clam,” or mouth, to perform correctly.
... which is anything but definitive. Other possibilities listed in the piece are softened by statements like "it seems entirely logical that ..."
So can anybody provide an actual origin story for use of this term in this context?