Source : Webster's Revised Unabridged Dictionary (1913)

Spider web \Spi"der web"\, or Spider's web \Spi"der's web"\ .
   (Zo["o]l.)
   The silken web which is formed by most kinds of spiders,
   particularly the web spun to entrap their prey. See
   {Geometric spider}, {Triangle spider}, under {Geometric}, and
   {Triangle}.

Source : WordNet®

spider's web
     n 1: a web resembling the webs spun by spiders [syn: {spider web}]
     2: a web spun by spiders to trap insect prey [syn: {spider web}]