The Collaborative International Dictionary of English v.0.48:

Municipal \Mu*nic"i*pal\, a. [L. municipalis, fr. municipium a
   town, particularly in Italy, which possessed the right of
   Roman citizenship, but was governed by its own laws, a free
   town, fr. municeps an inhabitant of a free town, a free
   citizen; munia official duties, functions + capere to take:
   cf. F. municipal. Cf. Immunity, and Capacoius.]
   1. Of or pertaining to a city or a corporation having the
      right of administering local government; as, municipal
      rights; municipal officers.
      [1913 Webster]

   2. Of or pertaining to a state, kingdom, or nation.
      [1913 Webster]

            Municipal law is properly defined to be a rule of
            civil conduct prescribed by the supreme power in a
            state.                                --Blackstone.
      [1913 Webster]

WordNet (r) 3.0 (2006):

municipal
    adj 1: relating or belonging to or characteristic of a
           municipality; "municipal government"; "municipal bonds";
           "a municipal park"; "municipal transportation"
    2: of or relating to the government of a municipality;
       "international law...only authorizes a belligerent to punish
       a spy under its municipal law"- J.L.kuntz

Moby Thesaurus II by Grady Ward, 1.0:

24 Moby Thesaurus words for "municipal":
   borough, burghal, citified, city, civic, civil, council, downtown,
   home, inland, internal, interurban, intestine, metropolitan,
   midtown, national, native, oppidan, parish, suburban, town, uptown,
   urban, village



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

MUNICIPAL. Strictly, this word applies only to what belongs to a city. Among
the Romans, cities were called municipia; these cities voluntarily joined
the Roman republic in relation to their sovereignty only, retaining, their
laws, their liberties, and their magistrates, who were thence called
municipal magistrates. With us this word has a more extensive meaning; for
example, we call municipal law, not the law of a city only, but the law of
the state. 1 Bl. Com. Municipal is used in contradistinction to
international; thus we say an offence against the law of nations is an
international offence, but one committed against a particular state or
separate community, is a municipal offence.