The Collaborative International Dictionary of English v.0.48:

Ruminate \Ru"mi*nate\, v. i. [imp. & p. p. Ruminated; p. pr. &
   vb. n. Ruminating.] [L. ruminatus, p. p. of ruminari,
   ruminare, fr. rumen, -inis, throat, akin to ructare to belch,
   erugere to belch out, Gr. ?, AS. roccettan.]
   1. To chew the cud; to chew again what has been slightly
      chewed and swallowed. "Cattle free to ruminate."
      --Wordsworth.
      [1913 Webster]

   2. Fig.: To think again and again; to muse; to meditate; to
      ponder; to reflect. --Cowper.
      [1913 Webster]

            Apart from the hope of the gospel, who is there that
            ruminates on the felicity of heaven?  --I. Taylor.
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Ruminate \Ru"mi*nate\, v. t.
   1. To chew over again.
      [1913 Webster]

   2. Fig.: To meditate or ponder over; to muse on.
      [1913 Webster]

            Mad with desire, she ruminates her sin. --Dryden.
      [1913 Webster]

            What I know
            Is ruminated, plotted, and set down.  --Shak.
      [1913 Webster] Ruminate

The Collaborative International Dictionary of English v.0.48:

Ruminate \Ru"mi*nate\, Ruminated \Ru"mi*na`ted\, a. (Bot.)
   Having a hard albumen penetrated by irregular channels filled
   with softer matter, as the nutmeg and the seeds of the North
   American papaw.
   [1913 Webster]

WordNet (r) 3.0 (2006):

ruminate
    v 1: chew the cuds; "cows ruminate"
    2: reflect deeply on a subject; "I mulled over the events of the
       afternoon"; "philosophers have speculated on the question of
       God for thousands of years"; "The scientist must stop to
       observe and start to excogitate" [syn: chew over, think
       over, meditate, ponder, excogitate, contemplate,
       muse, reflect, mull, mull over, ruminate,
       speculate]

Moby Thesaurus II by Grady Ward, 1.0:

56 Moby Thesaurus words for "ruminate":
   be abstracted, bite, brood, brood over, champ, chaw, chew,
   chew over, chew the cud, chew up, chomp, chump, con over, consider,
   contemplate, crunch, debate, deliberate, deliberate over,
   deliberate upon, digest, excogitate, gnash, gnaw, grind, gum,
   introspect, masticate, meditate, meditate upon, mouth, mull over,
   mumble, munch, muse, muse on, muse over, nibble, perpend,
   play around with, play with, ponder, ponder over, reflect,
   reflect over, revolve, roll, ruminate over, run over, scrunch,
   speculate, study, think over, toy with, turn over, weigh