Source : Webster's Revised Unabridged Dictionary (1913)

Spinneret \Spin"ner*et\, n. (Zo["o]l.)
   One of the special jointed organs situated on the under side,
   and near the end, of the abdomen of spiders, by means of
   which they spin their webs. Most spiders have three pairs of
   spinnerets, but some have only two pairs. The ordinary silk
   line of the spider is composed of numerous smaller lines
   jointed after issuing from the spinnerets.