[1] : 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
see also:
shortened ? shortening short to shorten a rope to shorten sail 

[2] : The Collaborative International Dictionary of English v.0.48

shortening \short"ening\, n.
   1. the act of making or becoming short or shorter.
      1913 webster

   2. cookery that which renders pastry short or friable, as
      butter, lard, etc.
      1913 webster

[3] : WordNet (r) 2.0

shortening
     n 1: fat such as butter or lard used in baked goods
     2: act of decreasing in length; "the dress needs shortening"

Shortening >> S Words
Shortening, definition of term: Shortening
shortening_pag1.html