1. [n]  a small cosmetics case with a mirror; to be carried in a woman's purse
2. [n]  a small and economical car
3. [n]  a signed written agreement between two or more parties (nations) to perform some action
4. [adj]  closely and firmly united or packed together; "compact soil"; "compact clusters of flowers"
5. [adj]  closely crowded together; "a compact shopping center"; "a dense population"; "thick crowds"
6. [adj]  briefly giving the gist of something; "a short and compendious book"; "a compact style is brief and pithy"; "succinct comparisons"; "a summary formulation of a wide-ranging subject"
7. [adj]  heavy and compact in form or stature; "a wrestler of compact build"; "he was tall and heavyset"; "stocky legs"; "a thick middle-aged man"; "a thickset young man"
8. [v]  squeeze or press together; "she compressed her lips"; "the muscle contracted"
9. [v]  make more compact by or as if by pressing; "compress the data"
10. [v]  compress into a wad; "wad paper into the box"
11. [v]  have the property of being packable or compactable or of compacting easily; "This powder compacts easily"; "Such odd-shaped items do not pack well"

1. \Com*pact"\ (k[o^]m*p[a^]kt"), p. p. & a [L. compactus,
   p. p. of compingere to join or unite; com- + pangere to
   fasten, fix: cf. F. compacte. See {Pact}.]
   1. Joined or held together; leagued; confederated. [Obs.]
      ``Compact with her that's gone.'' --Shak.
            A pipe of seven reeds, compact with wax together.
                                                  --Peacham.
   2. Composed or made; -- with of. [Poetic]
            A wandering fire, Compact of unctuous vapor.
                                                  --Milton.
   3. Closely or firmly united, as the particles of solid
      bodies; firm; close; solid; dense.
            Glass, crystal, gems, and other compact bodies.
                                                  --Sir I.
                                                  Newton.
   4. Brief; close; pithy; not diffuse; not verbose; as, a
      compact discourse.
   Syn: Firm; close; solid; dense; pithy; sententious.
   

2. \Com*pact"\, v. t. [imp. & p. p. {Compacted}; p. pr. &
   vb. n. {Compacting}.]
   1. To thrust, drive, or press closely together; to join
      firmly; to consolidate; to make close; -- as the parts
      which compose a body.
            Now the bright sun compacts the precious stone.
                                                  --Blackstone.
   2. To unite or connect firmly, as in a system.
            The whole body fitly joined together and compacted
            by that which every joint supplieth.  --Eph. iv. 16.
   

3. \Com"pact\, n. [L. compactum, fr. compacisci, p. p.
   compactus, to make an agreement with; com- + pacisci to make
   an agreement. See {Pact}.]
   An agreement between parties; a covenant or contract.
         The law of nations depends on mutual compacts,
         treaties, leagues, etc.                  --Blackstone.
         Wedlock is described as the indissoluble compact.
                                                  --Macaulay.
         The federal constitution has been styled a compact
         between the States by which it was ratified. --Wharton.
   Syn: See {Covenant}.
   

1. (Or "finite", "isolated") In domain theory, an element d of a cpo D is compact if and only if, for any chain S, a subset of D,

        d <= lub S  =>  there exists s in S such that d <= s.

I.e. you always reach d (or better) after a finite number of steps up the chain.

("<=" is written in LaTeX as \sqsubseteq).

[Jargon File]

2. Of a design, describes the valuable property that it can all be apprehended at once in one's head. This generally means the thing created from the design can be used with greater facility and fewer errors than an equivalent tool that is not compact. Compactness does not imply triviality or lack of power; for example, C is compact and Fortran is not, but C is more powerful than Fortran. Designs become non-compact through accreting features and cruft that don't merge cleanly into the overall design scheme (thus, some fans of Classic C maintain that ANSI C is no longer compact).