Source : Webster's Revised Unabridged Dictionary (1913)

Delta \Del"ta\, n.; pl. {Deltas}. [Gr. de`lta, the name of the
   fourth letter of the Greek alphabet (the capital form of
   which is [Delta], Eng. D), from the Ph[oe]nician name of the
   corresponding letter. The Greeks called the alluvial deposit
   at the mouth of the Nile, from its shape, the Delta of the
   Nile.]
   A tract of land shaped like the letter delta ([Delta]),
   especially when the land is alluvial and inclosed between two
   or more mouths of a river; as, the delta of the Ganges, of
   the Nile, or of the Mississippi.

Delta \Del"ta\, n.
   1. The fourth letter of the Greek alphabet ([Delta] [delta]),
      answering to {D}. Hence, an object having the shape of the
      capital [Delta].

   2. (Elec.) The closed figure produced by connecting three
      coils or circuits successively, end for end, esp. in a
      three-phase system; -- often used attributively, as delta
      winding, delta connection (which see), etc.

Source : WordNet®

delta
     n 1: a low triangular area where a river divides before entering
          a larger body of water
     2: the 4th letter of the Greek alphabet

Source : Free On-Line Dictionary of Computing

delta
     
        1. A quantitative change, especially a small or incremental
        one (this use is general in physics and engineering).  "I just
        doubled the speed of my program!"  "What was the delta on
        program size?"  "About 30 percent."  (He doubled the speed of
        his program, but increased its size by only 30 percent.)
     
        2. [Unix] A {diff}, especially a {diff} stored under the set
        of version-control tools called SCCS (Source Code Control
        System) or RCS (Revision Control System).  See {change
        management}.
     
        3. A small quantity, but not as small as {epsilon}.  The
        jargon usage of {delta} and {epsilon} stems from the
        traditional use of these letters in mathematics for very small
        numerical quantities, particularly in "epsilon-delta" proofs
        in limit theory (as in the differential calculus).  The term
        {delta} is often used, once {epsilon} has been mentioned, to
        mean a quantity that is slightly bigger than {epsilon} but
        still very small.  "The cost isn't epsilon, but it's delta"
        means that the cost isn't totally negligible, but it is
        nevertheless very small.  Common constructions include "within
        delta of ---", "within epsilon of ---": that is, "close to"
        and "even closer to".
     
        [{Jargon File}]
     
        (2000-08-02)

Delta
     
        
     
        1. An expression-based language developed by J.C. Cleaveland
        in 1978.
     
        2. A string-processing language with single-character commands
        from {Tandem Computers}.
     
        3. A language for system specification of simulation
        execution.
     
        ["System Description and the DELTA Language",
        E. Holback-Hansen et al, DELTA Proj Rep 4, Norweg Comput Ctr,
        Feb 1977].
     
        4. A {COBOL} generating language produced by {Delta Software
        Entwicklung GmbH (http://www.delta-software.de/)}.
     
        (2000-08-02)