A comment elsewhere prompted me to drag out recollections of words whose meaning I misunderstood as a child:
I thought this meant "exactly." Back in the days when TV stations would sign off for the night, the listings for the first programs of the day would give the time as "6:00 AM, approximately," and I thought about getting up early to see a program that actually began at 6 AM, instead of at 6:02 or 6:03 after the inevitable ads. I would have been very disappointed if I had bothered.
I thought this meant that something in view had to be moving. I'm not sure what counted as "moving." Branches waving in the wind? Probably not. A flowing stream? I doubt it. Animals galloping by? Possibly. Where I got this idea (or indeed most of these ideas) I have no notion. I spent a lot of time on vacation scorning signs that read "scenic view" because that view was entirely stationary.
I thought this meant you were literally struck blind if you looked in that direction - whether permanently or momentarily I wasn't sure and didn't want to find out the hard way. I specifically remember our coming across a road sign with this warning when we were out driving around house-hunting in the hill country, which would put my age at 7. It is characteristic of me that, well over a half century later, I still remember exactly where this was, even though I've never gone back to check if the sign is still there. (I might be struck blind!) But from Google street view, apparently not.
*out of wedlock
I thought this meant as a result of wedlock. You can imagine how much confusion that caused.
I thought that to call someone "a contemporary of N" meant they were a successor in the tradition of N, no chronological overlap required. My father was of the firm opinion that whenever his children raised a fuss, they were putting it on and faking it. Since we never did that, this view caused much distress. In the process he would call us a bunch of little Sarah Bernhardts. This depiction as a notorious over-actor is the only context in which I ever heard the name of Sarah Bernhardt in childhood. I thought it was therefore accurate to say that he considered us contemporaries of Sarah Bernhardt.
Speaking of my father,
He did not consider this a legitimate word, but I never realized that. Whenever - and I mean literally whenever - one of us kids would call out "Hey!" in his presence, my father would say, "Hay is what horses eat." But the lesson never took. Because we said "Hey!" reflexively, without conscious intent or even awareness, the labored pun made no impression, and I spent my childhood believing that "Hay is what horses eat" was a complete non sequitur of a statement that my father would utter at random intervals for no apparent reason. I must have been well into adulthood when the penny finally dropped.