The Collaborative International Dictionary of English v.0.48:

Rosary \Ro"sa*ry\, n.; pl. Rosaries. [LL. rosarium a string of
   beads, L. rosarium a place planted with roses, rosa a rose:
   cf. F. rosaire. See Rose.]
   1. A bed of roses, or place where roses grow. "Thick rosaries
      of scented thorn." --Tennyson.
      [1913 Webster]

   2. (R.C.Ch.) A series of prayers (see Note below) arranged to
      be recited in order, on beads; also, a string of beads by
      which the prayers are counted.
      [1913 Webster]

            His idolized book, and the whole rosary of his
            prayers.                              --Milton.
      [1913 Webster]

   Note: A rosary consists of fifteen decades. Each decade
         contains ten Ave Marias marked by small beads, preceded
         by a Paternoster, marked by a larger bead, and
         concluded by a Gloria Patri. Five decades make a
         chaplet, a third part of the rosary. --Bp. Fitzpatrick.
         [1913 Webster]

   3. A chapelet; a garland; a series or collection, as of
      beautiful thoughts or of literary selections.
      [1913 Webster]

            Every day propound to yourself a rosary or chaplet
            of good works to present to God at night. --Jer.
                                                  Taylor.
      [1913 Webster]

   4. A coin bearing the figure of a rose, fraudulently
      circulated in Ireland in the 13th century for a penny.
      [1913 Webster]

   Rosary shell (Zool.), any marine gastropod shell of the
      genus Monodonta. They are top-shaped, bright-colored and
      pearly.
      [1913 Webster]

WordNet (r) 3.0 (2006):

rosary
    n 1: a string of beads used in counting prayers (especially by
         Catholics) [syn: rosary, prayer beads]

Moby Thesaurus II by Grady Ward, 1.0:

87 Moby Thesaurus words for "rosary":
   Agnus Dei, Angelus, Ave, Ave Maria, Hail Mary, Holy Grail, Host,
   Kyrie Eleison, Paternoster, Pieta, Sanctus bell, Sangraal,
   aid prayer, appeal, ark, asperger, asperges, aspergillum, bambino,
   beadroll, beads, beseechment, bidding prayer, breviary, candle,
   censer, chaplet, ciborium, collect, communion, contemplation,
   cross, crucifix, cruet, devotions, entreaty, eucharistial, grace,
   holy cross, holy water, holy-water sprinkler, icon, impetration,
   imploration, incensory, intercession, invocation, litany, matzo,
   meditation, menorah, mezuzah, mikvah, monstrance, obsecration,
   obtestation, orison, osculatory, ostensorium, paschal candle, pax,
   petition, phylacteries, prayer, prayer shawl, prayer wheel, pyx,
   relics, rogation, rood, sacramental, sacred relics, sacring bell,
   shofar, silent prayer, suit, sukkah, supplication, tabernacle,
   tallith, thanks, thanksgiving, thurible, urceole, veronica,
   vigil light, votive candle