I'm all on edge!

The expression "on tenterhooks" cropped up the other day.  It means to be in a state of (rather uncomfortable) suspense, and contrary to what a lot of people think, it has nothing to do with tents.  A tenter was a wooden frame on which woven fabric used to be stretched out to dry, and to stop it shrinking it was held in place by - you've guessed it - tenterhooks, little hooks around the edges.  So the cloth was kept under tension, and hence the metaphor of people being under tension was born.