The Collaborative International Dictionary of English v.0.48:

Synthesis \Syn"the*sis\, n.; pl. Syntheses. [L., a mixture,
   properly, a putting together, Gr. ?, fr. ? to place or put
   together; sy`n with + ? to place. See Thesis.]
   1. Composition, or the putting of two or more things
      together, as in compounding medicines.
      [1913 Webster]

   2. (Chem.) The art or process of making a compound by putting
      the ingredients together, as contrasted with analysis;
      thus, water is made by synthesis from hydrogen and oxygen;
      hence, specifically, the building up of complex compounds
      by special reactions, whereby their component radicals are
      so grouped that the resulting substances are identical in
      every respect with the natural articles when such occur;
      thus, artificial alcohol, urea, indigo blue, alizarin,
      etc., are made by synthesis.
      [1913 Webster]

   3. (Logic) The combination of separate elements of thought
      into a whole, as of simple into complex conceptions,
      species into genera, individual propositions into systems;
      -- the opposite of analysis.
      [1913 Webster]

            Analysis and synthesis, though commonly treated as
            two different methods, are, if properly understood,
            only the two necessary parts of the same method.
            Each is the relative and correlative of the other.
                                                  --Sir W.
                                                  Hamilton.
      [1913 Webster]

WordNet (r) 3.0 (2006):

synthesis
    n 1: the process of producing a chemical compound (usually by
         the union of simpler chemical compounds)
    2: the combination of ideas into a complex whole [syn:
       synthesis, synthetic thinking] [ant: analysis,
       analytic thinking]
    3: reasoning from the general to the particular (or from cause
       to effect) [syn: deduction, deductive reasoning,
       synthesis]

Moby Thesaurus II by Grady Ward, 1.0:

104 Moby Thesaurus words for "synthesis":
   Anschluss, Baconian method, a fortiori reasoning,
   a posteriori reasoning, a priori reasoning, addition, affiliation,
   agglomeration, aggregation, agreement, alliance, amalgamation,
   analysis, assemblage, assembly, assimilation, association, blend,
   blending, building, buildup, cabal, cartel, centralization,
   coalescence, coalition, combination, combine, combining, combo,
   composite, composition, compound, confederacy, confederation,
   congeries, conglomeration, conjugation, conjunction, consolidation,
   conspiracy, constitution, construction, deduction,
   deductive reasoning, ecumenism, embodiment, encompassment, enosis,
   epagoge, fabrication, fashioning, federalization, federation,
   formation, fusing, fusion, generalization, getup, hookup,
   hypothesis and verification, identification, inclusion,
   incorporation, induction, inductive reasoning, inference,
   integrating, integration, junction, junta, league, make, makeup,
   marriage, meld, melding, merge, merger, merging, mixing, mixture,
   organization, package, package deal, particularization,
   philosophical induction, piecing together, putting together, setup,
   shaping, solidification, structure, structuring, syllogism,
   syllogistic reasoning, syncretism, syndication, syneresis, tie-up,
   unification, unifying, union, wedding



The Free On-line Dictionary of Computing (30 December 2018):

synthesis

    The process of deriving
   (efficient) programs from (clear) specifications.

   See also program transformation.

   (1996-08-23)