Source : Webster's Revised Unabridged Dictionary (1913)

Enter \En"ter\, v. t. [imp. & p. p. {Entered}; p. pr. & vb. n.
   {Entering}.] [OE. entren, enteren, F. entrer, fr. L. intrare,
   fr. intro inward, contr. fr. intero (sc. loco), fr. inter in
   between, between. See {Inter-}, {In}, and cf. {Interior}.]
   1. To come or go into; to pass into the interior of; to pass
      within the outer cover or shell of; to penetrate; to
      pierce; as, to enter a house, a closet, a country, a door,
      etc.; the river enters the sea.

            That darksome cave they enter.        --Spenser.

            I, . . . with the multitude of my redeemed, Shall
            enter heaven, long absent.            --Milton.

   2. To unite in; to join; to be admitted to; to become a
      member of; as, to enter an association, a college, an
      army.

   3. To engage in; to become occupied with; as, to enter the
      legal profession, the book trade, etc.

   4. To pass within the limits of; to attain; to begin; to
      commence upon; as, to enter one's teens, a new era, a new
      dispensation.

   5. To cause to go (into), or to be received (into); to put
      in; to insert; to cause to be admitted; as, to enter a
      knife into a piece of wood, a wedge into a log; to enter a
      boy at college, a horse for a race, etc.

   6. To inscribe; to enroll; to record; as, to enter a name, or
      a date, in a book, or a book in a catalogue; to enter the
      particulars of a sale in an account, a manifest of a ship
      or of merchandise at the customhouse.

   7. (Law)
      (a) To go into or upon, as lands, and take actual
          possession of them.
      (b) To place in regular form before the court, usually in
          writing; to put upon record in proper from and order;
          as, to enter a writ, appearance, rule, or judgment.
          --Burrill.

   8. To make report of (a vessel or her cargo) at the
      customhouse; to submit a statement of (imported goods),
      with the original invoices, to the proper officer of the
      customs for estimating the duties. See {Entry}, 4.

   9. To file or inscribe upon the records of the land office
      the required particulars concerning (a quantity of public
      land) in order to entitle a person to a right pf
      pre["e]mption. [U.S.] --Abbott.

   10. To deposit for copyright the title or description of (a
       book, picture, map, etc.); as, ``entered according to act
       of Congress.''

   11. To initiate; to introduce favorably. [Obs.] --Shak.

Enter \En"ter\, v. i.
   1. To go or come in; -- often with in used pleonastically;
      also, to begin; to take the first steps. ``The year
      entering.'' --Evelyn.

            No evil thing approach nor enter in.  --Milton.

            Truth is fallen in the street, and equity can not
            enter.                                --Is. lix. 14.

            For we which have believed do enter into rest.
                                                  --Heb. iv. 3.

   2. To get admission; to introduce one's self; to penetrate;
      to form or constitute a part; to become a partaker or
      participant; to share; to engage; -- usually with into;
      sometimes with on or upon; as, a ball enters into the
      body; water enters into a ship; he enters into the plan;
      to enter into a quarrel; a merchant enters into
      partnership with some one; to enter upon another's land;
      the boy enters on his tenth year; to enter upon a task;
      lead enters into the composition of pewter.

   3. To penetrate mentally; to consider attentively; -- with
      into.

            He is particularly pleased with . . . Sallust for
            his entering into internal principles of action.
                                                  --Addison.

Source : WordNet®

enter
     v 1: to come or go into; "the boat entered an area of shallow
          marshes" [syn: {come in}, {get into}, {get in}, {go into},
           {go in}, {move into}] [ant: {exit}]
     2: become a participant; be involved in; "enter a race"; "enter
        an agreement"; "enter a drug treatment program"; "enter
        negotiations" [syn: {participate}] [ant: {drop out}]
     3: register formally as a participant or member; "The party
        recruited many new members" [syn: {enroll}, {inscribe}, {enrol},
         {recruit}]
     4: be or play a part of or in; "Elections figure prominently in
        every government program"; "How do the elections figure in
        the current pattern of internal politics?" [syn: {figure}]
     5: make a record of; set down in permanent form [syn: {record},
         {put down}]
     6: come on stage
     7: put or introduce into something; "insert a picture into the
        text" [syn: {insert}, {infix}, {introduce}]
     8: take on duties or office; "accede to the throne" [syn: {accede}]
     9: set out on (an enterprise, subject of study, etc.); "she
        embarked upon a new career" [syn: {embark}]