The Collaborative International Dictionary of English v.0.48:

Prosecution \Pros`e*cu"tion\, n. [L. prosecutio a following.]
   1. The act or process of prosecuting, or of endeavoring to
      gain or accomplish something; pursuit by efforts of body
      or mind; as, the prosecution of a scheme, plan, design, or
      undertaking; the prosecution of war.
      [1913 Webster]

            Keeping a sharp eye on her domestics . . . in
            prosecution of their various duties.  --Sir W.
                                                  Scott.
      [1913 Webster]

   2. (Law)
      (a) The institution and carrying on of a suit in a court
          of law or equity, to obtain some right, or to redress
          and punish some wrong; the carrying on of a judicial
          proceeding in behalf of a complaining party, as
          distinguished from defense.
      (b) The institution, or commencement, and continuance of a
          criminal suit; the process of exhibiting formal
          charges against an offender before a legal tribunal,
          and pursuing them to final judgment on behalf of the
          state or government, as by indictment or information.
      (c) The party by whom criminal proceedings are instituted.
          --Blackstone. Burrill. Mozley & W.
          [1913 Webster]

WordNet (r) 3.0 (2006):

prosecution
    n 1: the institution and conduct of legal proceedings against a
         defendant for criminal behavior [syn: prosecution,
         criminal prosecution] [ant: defence, defense,
         demurrer, denial]
    2: the lawyers acting for the state to put the case against the
       defendant [ant: defence, defense, defense lawyers,
       defense team]
    3: the continuance of something begun with a view to its
       completion [syn: pursuance, prosecution]

Moby Thesaurus II by Grady Ward, 1.0:

72 Moby Thesaurus words for "prosecution":
   accusal, accusation, accusing, action, allegation, allegement,
   arraignment, bill of particulars, blame, bringing of charges,
   bringing to book, carrying out, case, cause, cause in court,
   charge, chase, complaint, completion, count, delation,
   denouncement, denunciation, discharge, dogging, effectuation,
   enforcement, execution, follow, follow-up, following, fulfillment,
   hue and cry, hunting, impeachment, implication, imputation,
   indictment, information, innuendo, insinuation, judicial process,
   lawsuit, laying of charges, legal action, legal case,
   legal proceedings, legal process, legal remedy, litigation,
   observance, plaint, proceedings, pursuance, pursuing, pursuit,
   quest, reproach, searching, seeking, shadowing, stalking, suit,
   suit at law, taxing, tracking, tracking down, trailing,
   transaction, true bill, unspoken accusation, veiled accusation



Bouvier's Law Dictionary, Revised 6th Ed (1856):

PROSECUTION, crim. law. The means adopted to bring a supposed offender to
justice and punishment by due course of law.
     2. Prosecutions are carried on in the name of the government, and have
for their principal object the security and happiness of the people in
general. Hawk. B. 2, c. 25, s. 3; Bac. Ab. Indictment, A 3.
     3. The modes most usually employed to carry them on, are by indictment;
1 Chit. Cr. Law, 132; presentment of a grand jury; Ibid. 133; coroner's
inquest; Ibid. 134; and by an information. Vide Merl. Repert. mot
Accusation.