tenterhooks, (n): metal hooks used by tent-makers to stretch and hold cloth while making a tent.
to be on tenterhooks: (expresssion) to be held in a state of painful suspense or impatience. The OED finds the earliest use of this expression in Tobias Smollett’s 1748 work The Adventures of Roderick Random: “I left him upon the tenter-hooks of impatient uncertainty.” (Sources: OED, Merriam-Webster Online)
Example from the news: Pogatetz on tenterhooks: “Emanuel Pogatetz will have to wait another week before learning the outcome of his appeal.”
Example from Scripture: Don’t stretch yourself on tenterhooks over what you are to eat or drink or wear. Only the faithless entertain such worries. Your heavenly Father already knows all that you need, and he will provide it all to you daily if you put him first and make His Kingdom your highest priority. —Matthew 6:31-33 (Jesus speaking)
Caution: Americans sometimes mistakenly say and write this word as tenderhooks.