Jackknifed

2 : to turn and form an angle of 90 degrees or less with each other -- used especially of a tractor-trailer combination

Yesterday, I finally learned what "jackknifed" means while listening to the traffic report. I've always thought it was just some type of trailer, a mechanical term that I have an idea of but don't have a real need to understand. Like a 4X4 or all-wheel drive. A jackknifed tractor-trailer.

For whatever reason, the reporter simply explained what it was, which nobody ever does. I didn't even know that I didn't know what it meant...

I'd like to uncover more blindspots that would actually be useful in my life.