The Collaborative International Dictionary of English v.0.48:

Meditation \Med`i*ta"tion\, n. [OE. meditacioun, F.
   m['e]ditation, fr. L. meditatio.]
   1. The act of meditating; close or continued thought; the
      turning or revolving of a subject in the mind; serious
      contemplation; reflection; musing.
      [1913 Webster]

            Let the words of my mouth and the meditation of my
            heart be acceptable in thy sight.     --Ps. xix. 14.
      [1913 Webster]

   2. Thought; -- without regard to kind. [Obs.]
      [1913 Webster]

            With wings as swift
            As meditation or the thoughts of love. --Shak.
      [1913 Webster]

WordNet (r) 3.0 (2006):

meditation
    n 1: continuous and profound contemplation or musing on a
         subject or series of subjects of a deep or abstruse nature;
         "the habit of meditation is the basis for all real
         knowledge" [syn: meditation, speculation]
    2: (religion) contemplation of spiritual matters (usually on
       religious or philosophical subjects)

Moby Thesaurus II by Grady Ward, 1.0:

114 Moby Thesaurus words for "meditation":
   Angelus, Ave, Ave Maria, Hail Mary, Kyrie Eleison, Paternoster,
   a wise passiveness, absorbed attention, absorption, advisement,
   aid prayer, appeal, application, beadroll, beads, beseechment,
   bidding prayer, breviary, brooding, chaplet, collect, communion,
   concentration, consideration, contemplation, contemplative life,
   counsel, deep study, deep thought, deliberation, devotions,
   do-nothing policy, do-nothingism, do-nothingness, dormancy,
   engagement, engrossment, entreaty, grace, idleness, immersion,
   immobility, impetration, imploration, inaction, inactivity,
   indolence, inertia, inertness, intentness, intercession,
   invocation, involvement, laissez-aller, laissez-faire,
   laissez-faireism, litany, lucubration, monomania, musing,
   neutralism, neutrality, neutralness, noninvolvement,
   nonparticipation, nonresistance, nonviolence,
   nonviolent resistance, obsecration, obsession, obtestation, orison,
   pacifism, paralysis, passive resistance, passive self-annihilation,
   passiveness, passivism, passivity, petition, policy, pondering,
   prayer, prayer wheel, preoccupation, procrastination,
   profound thought, quiescence, quietism, rapt attention, reflection,
   revolving, rogation, rosary, rumination, silent prayer,
   single-mindedness, speculation, stagnancy, stagnation,
   standpattism, stasis, studiousness, study, submersion, suit,
   supplication, thanks, thanksgiving, vegetation, vita contemplativa,
   waiting game, watching and waiting, weighing