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]

The Collaborative International Dictionary of English v.0.48:

Dilate \Di*late"\, v. i.
   1. To grow wide; to expand; to swell or extend in all
      directions.
      [1913 Webster]

            His heart dilates and glories in his strength.
                                                  --Addison.
      [1913 Webster]

   2. To speak largely and copiously; to dwell in narration; to
      enlarge; -- with on or upon.
      [1913 Webster]

            But still on their ancient joys dilate. --Crabbe.
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Dilate \Di*late"\, a.
   Extensive; expanded. [Obs.] --B. Jonson.
   [1913 Webster]

WordNet (r) 3.0 (2006):

dilate
    v 1: become wider; "His pupils were dilated" [syn: dilate,
         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, dilate] [ant:
       abbreviate, abridge, contract, cut, foreshorten,
       reduce, shorten]

Moby Thesaurus II by Grady Ward, 1.0:

79 Moby Thesaurus words for "dilate":
   add to, aggrandize, amplify, augment, bag, balloon, belly,
   belly out, bilge, billow, bloat, blow up, bouge, broaden, bug,
   build, build up, bulge, bulk, bulk out, crescendo, descant,
   describe, detail, develop, discuss, dissert, dissertate, distend,
   elaborate, enlarge, enlarge upon, evolve, expand, expatiate,
   explicate, extend, fill out, goggle, greaten, hike, hike up, huff,
   increase, inflate, lengthen, magnify, narrate, particularize,
   pooch, pop, pouch, pout, prolong, protract, puff, puff up, pump,
   pump up, raise, rarefy, recite, recount, rehearse,
   rehearse in extenso, relate, relate at large, round out, sermonize,
   snowball, stretch, sufflate, swell, swell out, tumefy, unfold, up,
   widen, work out