Last night at work, one of our reporters joked that he would "be on tenterhooks" waiting to see if the University of Kentucky made it into the National Invitation Tournament. According to the OED, to be on tenterhooks is to be "in a state of painful suspense or impatience." The NIT is a big disappointment for fans who are used to the Wildcats making it into the NCAA Tournament year after year, so his comment was heavy on the sarcasm. So, I wondered, what is a tenterhook. Well, it's a hook on a tenter. Duh.
Oh, you want more? OK.
According to Merriam-Webster Online, a tenter is "a frame or endless track with hooks or clips along two sides that is used for drying and stretching cloth." The OED's first recorded use of tenter is in 1408. The first recorded use of tenterhooks in the sense of "that on which something is stretched or strained; something that causes suffering or painful suspense" is in 1532.
I found a bit more on tenters at the Web site of the Trowbridge Museum in Britain.