The Collaborative International Dictionary of English v.0.48:

Rite \Rite\, n. [L. ritus; cf. Skr. r[imac]ti a stream, a
   running, way, manner, ri to flow: cf. F. rit, rite. CF.
   Rivulet.]
   The act of performing divine or solemn service, as
   established by law, precept, or custom; a formal act of
   religion or other solemn duty; a solemn observance; a
   ceremony; as, the rites of freemasonry.
   [1913 Webster]

         He looked with indifference on rites, names, and forms
         of ecclesiastical polity.                --Macaulay.
   [1913 Webster]

   Syn: Form; ceremony; observance; ordinance.
        [1913 Webster]

WordNet (r) 3.0 (2006):

rite
    n 1: an established ceremony prescribed by a religion; "the rite
         of baptism" [syn: rite, religious rite]
    2: any customary observance or practice [syn: ritual, rite]

Moby Thesaurus II by Grady Ward, 1.0:

87 Moby Thesaurus words for "rite":
   amenities, anniversaries, baccalaureate service, celebrating,
   celebration, ceremonial, ceremonies, ceremony, civilities,
   commemoration, commencement, convocation, custom, dignities,
   dressing ship, duty, elegancies, empty formality, exercise,
   exercises, fanfare, fanfaronade, festivity, flourish of trumpets,
   form, form of worship, formal, formalities, formality, formula,
   formulary, function, gentilities, graces, graduation,
   graduation exercises, holiday, holy rite, inaugural, inauguration,
   initiation, institution, jubilee, liturgy, marking the occasion,
   memorialization, memory, mode of worship, mummery, mystery,
   observance, occasion, office, order of worship, ordinance, ovation,
   performance, practice, prescribed form, procedure, rejoicing,
   religious ceremony, religious rites, remembrance, revel,
   rite de passage, rite of passage, rites, ritual, ritual observance,
   rituality, rituals, routine, sacrament, sacramental, salute, salvo,
   service, solemn observance, solemnity, solemnization, testimonial,
   testimonial banquet, testimonial dinner, toast, tribute, triumph



The Devil's Dictionary (1881-1906):

RITE, n.  A religious or semi-religious ceremony fixed by law, precept
or custom, with the essential oil of sincerity carefully squeezed out
of it.