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.
   [1913 Webster]

   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]

WordNet (r) 3.0 (2006):

tenterhook
    n 1: one of a series of hooks used to hold cloth on a tenter