I had no freakin' idea what a pergola was, I just called them "that thing that kind of looks like a patio roof but not really and usually people plant vines on them or something."
And then Allen, the ex-or-whatever-he-is used the word in front of me not long after we were dating.
It was kind of embarrassing to admit I didn't have any idea what he was talking about. He was pretty kind about it, though. He just pointed out one in someone's lawn/garden as we drove by.
YMMV, but in hindsight I think it's hilarious that I was so embarrassed just over not knowing what a word is. And now I totally have an occurrence of Baader-Meinhoff phenomenon every single time I see one. (Also, I got to teach a lot of people what Baader-Meinhoff phenomenon is in 2013!)
And I still think pergola is kind of a weird word.