The Collaborative International Dictionary of English v.0.48:

Compress \Com*press"\, v. t. [imp. & p. p. Compressed; p. pr &
   vb. n. Compressing.] [L. compressus, p. p. of comprimere to
   compress: com- + premere to press. See Press.]
   1. To press or squeeze together; to force into a narrower
      compass; to reduce the volume of by pressure; to compact;
      to condense; as, to compress air or water.
      [1913 Webster]

            Events of centuries . . . compressed within the
            compass of a single life.             --D. Webster.
      [1913 Webster]

            The same strength of expression, though more
            compressed, runs through his historical harangues.
                                                  --Melmoth.
      [1913 Webster]

   2. To embrace sexually. [Obs.] --Pope.
      [1913 Webster]

   3. (Computers) to reduce the space required for storage (of
      binary data) by an algorithm which converts the data to a
      smaller number of bits while preserving the information
      content. The compressed data is usually decompressed to
      recover the initial data format before subsequent use.
      [PJC]

   Syn: To crowd; squeeze; condense; reduce; abridge.
        [1913 Webster]

WordNet (r) 3.0 (2006):

compressing
    n 1: applying pressure [syn: compression, compressing] [ant:
         decompressing, decompression]