That's Weird

We were just driving home from Mom & Dad's in this huge downpour.  Flash flood type rainstorm, so loud that you couldn't hear anything but the rain thundering on the roof of the car. 
Nick says, "What's a sjdsofgi?"
Me: What?  Talk louder, I can't hear you over the rain.
Nick:  What's a SJDSOFGI?
Me: I still couldn't understand you.
Nick: What's a SHIRT?
Me: What's a shirt? (Really, that's what you need to know right this second?)
Nick: Yeah.
Me: (Umm....how do you answer that?) It's just a shirt.
Nick: Well, now that's weird!