The Collaborative International Dictionary of English v.0.48:

Democracy \De*moc"ra*cy\ (d[-e]*m[o^]k"r[.a]*s[y^]), n.; pl.
   Democracies (d[-e]*m[o^]k"r[.a]*s[i^]z). [F. d['e]mocratie,
   fr. Gr. dhmokrati`a; dh^mos the people + kratei^n to be
   strong, to rule, kra`tos strength.]
   1. Government by the people; a form of government in which
      the supreme power is retained and directly exercised by
      the people.
      [1913 Webster]

   2. Government by popular representation; a form of government
      in which the supreme power is retained by the people, but
      is indirectly exercised through a system of representation
      and delegated authority periodically renewed; a
      constitutional representative government; a republic.
      [1913 Webster]

   3. Collectively, the people, regarded as the source of
      government. --Milton.
      [1913 Webster]

   4. The principles and policy of the Democratic party, so
      called. [U.S.]
      [1913 Webster]

WordNet (r) 3.0 (2006):

democracy
    n 1: the political orientation of those who favor government by
         the people or by their elected representatives
    2: a political system in which the supreme power lies in a body
       of citizens who can elect people to represent them [syn:
       democracy, republic, commonwealth]
    3: the doctrine that the numerical majority of an organized
       group can make decisions binding on the whole group [syn:
       majority rule, democracy]

Moby Thesaurus II by Grady Ward, 1.0:

76 Moby Thesaurus words for "democracy":
   absolute monarchy, aristocracy, autarchy, autocracy, autonomy,
   coalition government, collective farm, collectivism, collectivity,
   collegiality, colonialism, common ownership, commonwealth,
   communal effort, communion, communism, community,
   constitutional government, constitutional monarchy, cooperation,
   cooperative society, dictatorship, dominion rule, duarchy,
   duumvirate, dyarchy, federal government, federation, feudal system,
   garrison state, gerontocracy, heteronomy, hierarchy, hierocracy,
   home rule, kibbutz, kolkhoz, limited monarchy, martial law,
   meritocracy, militarism, military government, mob rule, mobocracy,
   monarchy, neocolonialism, ochlocracy, oligarchy, pantisocracy,
   patriarchate, patriarchy, police state, profit sharing,
   public ownership, pure democracy, regency,
   representative democracy, representative government, republic,
   self-determination, self-government, sharecropping,
   social democracy, socialism, state ownership, stratocracy,
   technocracy, thearchy, theocracy, totalitarian government,
   totalitarian regime, town meeting, triarchy, triumvirate, tyranny,
   welfare state



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

DEMOCRACY, government. That form of government in which the sovereign power
is exercised by the people in a body, as was the practice in some of the
states of Ancient Greece; the term representative democracy has been given
to a republican government like that of the United States.