On Tenterhooks

After wool was woven, the finished cloth still held oil and dirt from the fleece that had to be washed out, and the wet cloth would then shrink and crease as it dried unless it was held taut. Cloth-makers stretched it on wooden frames called tenters (from the Latin "tendere," to stretch), fixed in place with hooked nails known as tenterhooks. The playwright John Ford recorded the related phrase "on the tenters" in his 1633 play The Broken Heart, and the specific wording "on tenterhooks" appears in Tobias Smollett's 1748 novel Roderick Random. The metaphor is direct: someone on tenterhooks is stretched tight with anxious anticipation, just like the cloth on the frame.