›If you say that you would like to be a fly on the wall on an occasion, you mean that you would like to hear what will be said or see what will happen while not being noticed: I'd love to be a fly on the wall when those two get home!
Are you a fan of shows like Doctor Who and Star Trek? Both shows have been around since the 1960s, and, not surprisingly, have generated some of their own vocabulary, some of which has now entered the Cambridge English Dictionary. The phenomenon of fandom, meaning “the state of being a fan of
a computer interface that provides information to users in normal, conversational speech in response to spoken requests Nearly every major tech company—from Amazon to Intel to Microsoft to Google—is chasing the sort of conversational user interface that Kaplan and his colleagues at PARC imagined decades ago.