Source : Webster's Revised Unabridged Dictionary (1913)

Commence \Com*mence"\, v. t.
   To enter upon; to begin; to perform the first act of.

         Many a wooer doth commence his suit.     --Shak.

   Note: It is the practice of good writers to use the verbal
         noun (instead of the infinitive with to) after
         commence; as, he commenced studying, not he commenced
         to study.

Commence \Com*mence"\, v. i. [imp. & p. p. {Commenced}; p. pr. &
   vb. n. {Commencing}.] [F. commencer, OF. comencier, fr. L.
   com- + initiare to begin. See {Initiate}.]
   1. To have a beginning or origin; to originate; to start; to
      begin.

            Here the anthem doth commence.        --Shak.

            His heaven commences ere the world be past.
                                                  --Goldsmith.

   2. To begin to be, or to act as. [Archaic]

            We commence judges ourselves.         --Coleridge.

   3. To take a degree at a university. [Eng.]

            I question whether the formality of commencing was
            used in that age.                     --Fuller.

Source : WordNet®

commence
     v 1: take the first step or steps in carrying out an action; "We
          began working at dawn"; "Who will start?"; "Get working
          as soon as the sun rises!"; "The first tourists began to
          arrive in Cambodia"; "He began early in the day"; "Let's
          get down to work now" [syn: {get down}, {begin}, {get},
          {start out}, {start}, {set about}, {set out}] [ant: {end}]
     2: set in motion, cause to start; "The U.S. started a war in
        the Middle East"; "The Iraqis began hostilities"; "begin a
        new chapter in your life" [syn: {begin}, {lead off}, {start}]
        [ant: {end}]
     3: get off the ground; "Who started this company?"; "We
        embarked on an exciting enterprise"; "I start my day with
        a good breakfast"; "We began the new semester"; "The
        afternoon session begins at 4 PM"; "The blood shed started
        when the partisans launched a surprise attack" [syn: {start},
         {start up}, {embark on}]