The Collaborative International Dictionary of English v.0.48:

Formalize \Form"al*ize\, v. i.
   To affect formality. [Obs.] --ales.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Formalize \Form"al*ize\ (f[^o]rm"al*[imac]z), v. t. [imp. & p.
   p. Formalized (f[^o]rm"al*[imac]zd); p. pr. & vb. n.
   Formalizing (f[^o]rm"al*[imac]`z[i^]ng).]
   1. To give form, or a certain form, to; to model. [R.]
      [1913 Webster]

   2. To render formal.
      [1913 Webster]

WordNet (r) 3.0 (2006):

formalize
    v 1: make formal or official; "We formalized the appointment and
         gave him a title" [syn: formalize, formalise]
    2: declare or make legally valid [syn: validate, formalize,
       formalise] [ant: annul, avoid, invalidate, nullify,
       quash, void]