Source : Webster's Revised Unabridged Dictionary (1913)

Dilate \Di*late"\, v. i.
   1. To grow wide; to expand; to swell or extend in all
      directions.

            His heart dilates and glories in his strength.
                                                  --Addison.

   2. To speak largely and copiously; to dwell in narration; to
      enlarge; -- with on or upon.

            But still on their ancient joys dilate. --Crabbe.

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.

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

            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.

Dilate \Di*late"\, a.
   Extensive; expanded. [Obs.] --B. Jonson.

Source : WordNet®

dilate
     v 1: become wider; "His pupils were dilated" [syn: {distend}]
     2: add details, as to an account or idea; clarify the meaning
        of and discourse in a learned way, usually in writing;
        "She elaborated on the main ideas in her dissertation"
        [syn: {elaborate}, {lucubrate}, {expatiate}, {exposit}, {enlarge},
         {flesh out}, {expand}, {expound}] [ant: {abridge}]