ten ‧ ter ‧ hooks /ˈtentəhʊks $ -ər-/ BrE AmE noun especially British English
[ Date: 1500-1600 ; Origin: tenterhook 'sharp nail for fastening cloth on a tenter' (15-20 centuries) , from tenter 'frame for drying and stretching cloth' (13-20 centuries) (from Medieval Latin tentura , from Latin tendere ; ⇨ ↑ tend ) + hook ]
be on tenterhooks to feel nervous and excited because you are waiting to find out something or for something to happen SYN be on edge :
She had been on tenterhooks all night, expecting Joe to return at any moment.