Source : Webster's Revised Unabridged Dictionary (1913)

Spinster \Spin"ster\, n. [Spin + -ster.]
   1. A woman who spins, or whose occupation is to spin.

            She spake to spinster to spin it out. --Piers
                                                  Plowman.

            The spinsters and the knitters in the sun. --Shak.

   2. A man who spins. [Obs.] --Shak.

   3. (Law) An unmarried or single woman; -- used in legal
      proceedings as a title, or addition to the surname.

            If a gentlewoman be termed a spinster, she may abate
            the writ.                             --Coke.

   4. A woman of evil life and character; -- so called from
      being forced to spin in a house of correction. [Obs.]

Source : WordNet®

spinster
     n 1: an elderly unmarried woman [syn: {old maid}]
     2: someone who spins (who twists fibers into threads) [syn: {spinner},
         {thread maker}]