Source : Webster's Revised Unabridged Dictionary (1913)

Tent \Tent\, n. [OE. tente, F. tente, LL. tenta, fr. L. tendere,
   tentum, to stretch. See {Tend} to move, and cf. {Tent} a roll
   of lint.]
   1. A pavilion or portable lodge consisting of skins, canvas,
      or some strong cloth, stretched and sustained by poles, --
      used for sheltering persons from the weather, especially
      soldiers in camp.

            Within his tent, large as is a barn.  --Chaucer.

   2. (Her.) The representation of a tent used as a bearing.

   {Tent bed}, a high-post bedstead curtained with a tentlike
      canopy.

   {Tent caterpillar} (Zo["o]l.), any one of several species of
      gregarious caterpillars which construct on trees large
      silken webs into which they retreat when at rest. Some of
      the species are very destructive to fruit trees. The most
      common American species is the larva of a bombycid moth
      ({Clisiocampa Americana}). Called also {lackery
      caterpillar}, and {webworm}.

Source : WordNet®

tent caterpillar
     n : the larvae of moths that build communal silken webs in
         orchard and shade trees