There’s a scene on a street corner. A lone woman shouts excitedly to herself, her arms gesturing through the air like she’s conducting the most maddening of symphonies. Years ago, she might have been crazy. In 2013, she’s
just on her Bluetooth. A passerby witnesses the outburst. But what if there is an audience of more than one? Are they “passersby” or “passerbys”?
Remember to pluralize the person, the passer, not the preposition. “Passersby” is correct here, even though you might want to tack that “s” onto the end of the word like most plural cases. You’ll notice this one incorrect in writing more than in speech. Do you use the correct spelling?