The Collaborative International Dictionary of English v.0.48:

Shorten \Short"en\, v. t. [imp. & p. p. Shortened ?; p. pr. &
   vb. n. Shortening.] [See Short, a.]
   1. To make short or shorter in measure, extent, or time; as,
      to shorten distance; to shorten a road; to shorten days of
      calamity.
      [1913 Webster]

   2. To reduce or diminish in amount, quantity, or extent; to
      lessen; to abridge; to curtail; to contract; as, to
      shorten work, an allowance of food, etc.
      [1913 Webster]

            Here, where the subject is so fruitful, I am
            shortened by my chain.                --Dryden.
      [1913 Webster]

   3. To make deficient (as to); to deprive; -- with of.
      [1913 Webster]

            Spoiled of his nose, and shortened of his ears.
                                                  --Dryden.
      [1913 Webster]

   4. To make short or friable, as pastry, with butter, lard,
      pot liquor, or the like.
      [1913 Webster]

   To shorten a rope (Naut.), to take in the slack of it.

   To shorten sail (Naut.), to reduce sail by taking it in.
      [1913 Webster]