The Collaborative International Dictionary of English v.0.48:

Cobweb \Cob"web`\, n. [Cob a spider + web.]
   1. The network spread by a spider to catch its prey.
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   2. A snare of insidious meshes designed to catch the ignorant
      and unwary.
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            I can not but lament thy splendid wit
            Entangled in the cobwebs of the schools. --Cowper.
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   3. That which is thin and unsubstantial, or flimsy and
      worthless; rubbish.
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            The dust and cobwebs of that uncivil age. --Sir P.
                                                  Sidney.
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   4. (Zool.) The European spotted flycatcher.
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   Cobweb lawn, a fine linen, mentioned in 1640 as being in
      pieces of fifteen yards. --Beck. Draper's Dict.
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            Such a proud piece of cobweb lawn.    --Beau. & Fl.

   Cobweb micrometer, a micrometer in which threads of cobweb
      are substituted for wires.
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