VERB (2)

1. make solid or more solid; cause to solidify;

2. become solid;
- Example: "The metal solidified when it cooled"

The Collaborative International Dictionary of English v.0.48:

Solidify \So*lid"i*fy\, v. t. [imp. & p. p. Solidified; p. pr.
   & vb. n. Solidifying.] [Solid + -fy: cf. F. solidifier.]
   To make solid or compact.
   [1913 Webster]

         Every machine is a solidified mechanical theorem. --H.
                                                  Spencer.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Solidify \So*lid"i*fy\, v. i.
   To become solid; to harden.
   [1913 Webster]

WordNet (r) 3.0 (2006):

solidify
    v 1: make solid or more solid; cause to solidify
    2: become solid; "The metal solidified when it cooled"