The Collaborative International Dictionary of English v.0.48:

Paean \P[ae]"an\ (p[=e]`an), n. [L. paean, Gr. paia`n, fr.
   Paia`n the physician of the gods, later, Apollo. Cf.
   P[ae]on, Peony.] [Written also pean.]
   1. An ancient Greek hymn in honor of Apollo as a healing
      deity, and, later, a song addressed to other deities.
      [1913 Webster]

   2. Any loud and joyous song; a song of triumph, joy, or
      praise. --Dryden. "Public p[ae]ans of congratulation."
      --De Quincey.
      [1913 Webster]

   3. See P[ae]on.
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

paeon \p[ae]"on\ (p[=e]"[o^]n), n. [L. paeon, Gr. paiw`n a
   solemn song, also, a p[ae]on, equiv. to paia`n. See
   P[ae]an.] (Anc. Poet.)
   A foot of four syllables, one long and three short, admitting
   of four combinations, according to the place of the long
   syllable. [Written also, less correctly, p[ae]an.]
   [1913 Webster]

WordNet (r) 3.0 (2006):

paean
    n 1: a formal expression of praise [syn: encomium, eulogy,
         panegyric, paean, pean]
    2: (ancient Greece) a hymn of praise (especially one sung in
       ancient Greece to invoke or thank a deity) [syn: paean,
       pean]

Moby Thesaurus II by Grady Ward, 1.0:

110 Moby Thesaurus words for "paean":
   Agnus Dei, Benedicite, Gloria, Gloria Patri, Gloria in Excelsis,
   Introit, Magnificat, Miserere, Negro spiritual, Nunc Dimittis,
   Te Deum, Trisagion, Vedic hymn, accolade, acknowledgment,
   adulation, alleluia, answer, anthem, antiphon, antiphony,
   apotheosis, applause, benediction, bepraisement, cantata, canticle,
   chant, cheer, chorale, chorus of cheers, church music, cognizance,
   congratulation, credit, crediting, cry, deification, doxology,
   eloge, encomium, eulogium, eulogy, exaltation, excessive praise,
   flattery, glorification, glory, gospel, gospel music, grace,
   hallelujah, hero worship, homage, hommage, honor, hooray, hosanna,
   hurrah, hurray, huzzah, hymn, hymn of praise, hymn-tune, hymnody,
   hymnography, hymnology, idolatry, idolizing, introit, kudos, laud,
   laudation, lionizing, magnification, mantra, mass, meed of praise,
   motet, offertory, offertory sentence, oratorio, overpraise,
   panegyric, passion, praise, prayer of thanks, prosodion, psalm,
   psalmody, rah, recessional, recognition, report, requiem,
   requiem mass, response, responsory, sacred music, shout, spiritual,
   thank offering, thank-you, thanks, thanksgiving, tribute, versicle,
   white spiritual, yell, yippee