The Collaborative International Dictionary of English v.0.48:

Compressed \Com*pressed"\, a.
   1. Pressed together; compacted; reduced in volume by
      pressure.
      [1913 Webster]

   2. (Bot.) Flattened lengthwise.
      [1913 Webster]

   Compressed-air engine, an engine operated by the elastic
      force of compressed air.
      [1913 Webster]

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):

compressed
    adj 1: pressed tightly together; "with lips compressed" [syn:
           compressed, tight]
    2: reduced in volume by pressure; "compressed air"
    3: flattened laterally along the whole length (e.g., certain
       leafstalks or flatfishes) [syn: compressed, flat]

Moby Thesaurus II by Grady Ward, 1.0:

104 Moby Thesaurus words for "compressed":
   Spartan, abbreviated, abridged, abstracted, aposiopestic, bobbed,
   brief, brusque, capsule, capsulized, clamped, clipped, close,
   close-knit, close-textured, close-woven, compact, compacted,
   compendious, concentrated, concise, concrete, condensed, congested,
   consolidated, constricted, contracted, crammed, crammed full,
   cramped, crisp, cropped, crowded, curt, curtailed, cut, cut short,
   dense, digested, docked, elided, elliptic, epigrammatic, firm,
   gluey, gnomic, hard, heavy, impenetrable, impermeable, jam-packed,
   jammed, knitted, laconic, massive, mowed, mown, nipped, nonporous,
   packed, pinched, pinched-in, pithy, pointed, pollard, polled,
   pruned, puckered, pursed, reaped, reserved, sententious, serried,
   shaved, sheared, short, short and sweet, short-cut, shortened,
   snub, snubbed, solid, solidified, squeezed, strangled,
   strangulated, substantial, succinct, summary, synopsized, taciturn,
   terse, thick, thick-growing, thickset, tight, to the point,
   trimmed, truncated, viscid, viscose, viscous, wasp-waisted,
   wrinkled