The Collaborative International Dictionary of English v.0.48:

Solidification \So*lid`i*fi*ca"tion\, n. [Cf. F.
   solidification.]
   Act of solidifying, or state of being solidified.
   [1913 Webster]

WordNet (r) 3.0 (2006):

solidification
    n 1: the process of becoming hard or solid by cooling or drying
         or crystallization; "the hardening of concrete"; "he tested
         the set of the glue" [syn: hardening, solidifying,
         solidification, set, curing]

Moby Thesaurus II by Grady Ward, 1.0:

166 Moby Thesaurus words for "solidification":
   Anschluss, abbreviation, accretion, addition, adherence, adhesion,
   affiliation, agglomeration, agglutination, aggregation, agreement,
   alliance, amalgamation, arteriosclerosis, assimilation,
   association, astriction, astringency, atherosclerosis, blend,
   blending, bottleneck, cabal, calcification, callusing, cartel,
   case hardening, centralization, cervix, circumscription, cling,
   clinging, clotting, clumping, clustering, coagulation, coalescence,
   coalition, coarctation, coherence, cohesion, cohesiveness,
   combination, combine, combo, compactedness, compaction,
   composition, compression, compressure, concentration, concretion,
   condensation, confederacy, confederation, congealment, congelation,
   congeries, conglobation, conglomeration, conjugation, conjunction,
   consolidation, conspiracy, constriction, constringency,
   contraction, contracture, cornification, crystallization,
   curtailment, decrease, densification, diminuendo, ecumenism,
   embodiment, encompassment, enosis, federalization, federation,
   firming, fossilization, fusion, granulation, hardening, hookup,
   hornification, hourglass, hourglass figure, identity, inclusion,
   incorporation, individuality, indivisibility, induration,
   inseparability, intactness, integrality, integration, integrity,
   inviolability, irreducibility, isthmus, junction, junta, knitting,
   lapidification, league, lithification, marriage, meld, melding,
   merger, narrow place, narrowing, neck, oneness, organic unity,
   ossification, package, package deal, particularity, petrifaction,
   petrification, puckering, purity, pursing, reduction, sclerosis,
   selfsameness, set, setting, shortening, simplicity, singleness,
   singularity, solidarity, solidity, steeling, sticking, stiffening,
   stranglement, strangulation, striction, stricture, syncretism,
   syndication, syneresis, synthesis, systole, tempering, tie-up,
   toughening, undividedness, unification, uniformity, union,
   uniqueness, unity, univocity, vitrifaction, vitrification,
   wasp waist, wedding, wholeness, wrinkling