The Collaborative International Dictionary of English v.0.48:

Congeal \Con*geal"\, v. t. [imp. & p. p. Congealed; p. pr. &
   vb. n. Congealing.] [F. congeler, L. congelare, -gelatumn;
   con- + gelare to freeze, gelu frost. See Gelid.]
   1. To change from a fluid to a solid state by cold; to
      freeze.

   Syn: jell, set.
        [1913 Webster]

              A vapory deluge lies to snow congealed. --Thomson.
        [1913 Webster]

   2. To affect as if by freezing; to check the flow of, or
      cause to run cold; to chill.
      [1913 Webster]

            As if with horror to congeal his blood. --Stirling.
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Congeal \Con*geal"\, v. i.
   To grow hard, stiff, or thick, from cold or other causes; to
   become solid; to freeze; to cease to flow; to run cold; to be
   chilled.

   Syn: jell, set.
        [1913 Webster]

              Lest zeal, now melted . . .
              Cool and congeal again to what it was. --Shak.
        [1913 Webster]

WordNet (r) 3.0 (2006):

congeal
    v 1: become gelatinous; "the liquid jelled after we added the
         enzyme" [syn: jell, set, congeal]

Moby Thesaurus II by Grady Ward, 1.0:

67 Moby Thesaurus words for "congeal":
   adhere, agglomerate, blast, blast-freeze, blight, bunch, cake,
   chill, clabber, clasp, cleave, clinch, cling, cling to, clot,
   clump, cluster, coagulate, cohere, concrete, conglomerate, cool,
   curd, curdle, dry, embrace, freeze, freeze solid, freeze to, gel,
   gelatinate, gelatinize, glaciate, glacify, grasp, grow together,
   hang on, hang together, hold, hold on, hold together, hug, ice,
   incrassate, indurate, inspissate, jell, jellify, jelly, knot,
   lopper, lump, mass, nip, persist, quick-freeze, refreeze, regelate,
   set, solidify, stay, stay put, stick, stick together, take hold of,
   thick, thicken