The Collaborative International Dictionary of English v.0.48:

Dilate \Di*late"\ (?; 277), v. t. [imp. & p. p. Dilated; p.
   pr. & vb. n. Dilating.] [L. dilatare; either fr. di- = dis-
   + latus wide, not the same word as latus, used as p. p. of
   ferre to bear (see Latitude); or fr. dilatus, used as p. p.
   of differre to separate (see Delay, Tolerate, Differ,
   and cf. Dilatory): cf. F. dilater.]
   1. To expand; to distend; to enlarge or extend in all
      directions; to swell; -- opposed to contract; as, the
      air dilates the lungs; air is dilated by increase of heat.
      [1913 Webster]

   2. To enlarge upon; to relate at large; to tell copiously or
      diffusely. [R.]
      [1913 Webster]

            Do me the favor to dilate at full
            What hath befallen of them and thee till now.
                                                  --Shak.

   Syn: To expand; swell; distend; enlarge; spread out; amplify;
        expatiate.
        [1913 Webster]