Source : Webster's Revised Unabridged Dictionary (1913)

Prayer \Pray"er\, n.
   One who prays; a supplicant.

Prayer \Prayer\ (?; 277), n. [OE. preiere, OF. preiere, F.
   pri[`e]re, fr. L. precarius obtained by prayer, fr. precari
   to pray. See {Pray}, v. i.]
   1. The act of praying, or of asking a favor; earnest request
      or entreaty; hence, a petition or memorial addressed to a
      court or a legislative body. ``Their meek preyere.''
      --Chaucer

   2. The act of addressing supplication to a divinity,
      especially to the true God; the offering of adoration,
      confession, supplication, and thanksgiving to the Supreme
      Being; as, public prayer; secret prayer.

            As he is famed for mildness, peace, and prayer.
                                                  --Shak.

   3. The form of words used in praying; a formula of
      supplication; an expressed petition; especially, a
      supplication addressed to God; as, a written or
      extemporaneous prayer; to repeat one's prayers.

            He made those excellent prayers which were published
            immediately after his death.          --Bp. Fell.

   {Prayer book}, a book containing devotional prayers.

   {Prayer meeting}, a meeting or gathering for prayer to God.

   Syn: Petition; orison; supplication; entreaty; suit.

Source : WordNet®

prayer
     n 1: the act of communicating with a deity (especially as a
          petition or in adoration or contrition or thanksgiving);
          "the priest sank to his knees in prayer" [syn: {supplication}]
     2: reverent petition to a deity [syn: {petition}, {orison}]
     3: earnest or urgent request; "an entreaty to stop the
        fighting"; "an appeal for help"; "an appeal to the public
        to keep calm" [syn: {entreaty}, {appeal}]
     4: a fixed text used in praying
     5: someone who prays to God [syn: {supplicant}]