The Collaborative International Dictionary of English v.0.48:
Tenter \Ten"ter\, n. [OE. tenture, tentoure, OF. tenture a
stretching, spreading, F. tenture hangings, tapestry, from L.
tendere, tentum, to stretch. See Tend to move.]
A machine or frame for stretching cloth by means of hooks,
called tenter-hooks, so that it may dry even and square.
Tenter ground, a place where tenters are erected.
Tenter-hook, a sharp, hooked nail used for fastening cloth
on a tenter.
To be on the tenters, To be on the tenter-hooks or To be
on tenterhooks, to be on the stretch; to be in distress,
uneasiness, or suspense. --Hudibras.
[1913 Webster +PJC]