The Collaborative International Dictionary of English v.0.48:

Economics \E`co*nom"ics\ ([=e]`k[o^]*n[o^]m"[i^]ks), n. [Gr. ta`
   o'ikonomika`, equiv. to "h o'ikonomi`a. See Economic.]
   1. The science of household affairs, or of domestic
      management.
      [1913 Webster]

   2. Political economy; the science of the utilities or the
      useful application of wealth or material resources; the
      study of the production, distribution, and consumption of
      goods and services of a nation or region, and its effect
      on the wealth of a country. See Political economy, under
      Political. "In politics and economics." --V. Knox.
      [1913 Webster +PJC]

WordNet (r) 3.0 (2006):

economics
    n 1: the branch of social science that deals with the production
         and distribution and consumption of goods and services and
         their management [syn: economics, economic science,
         political economy]

Moby Thesaurus II by Grady Ward, 1.0:

23 Moby Thesaurus words for "economics":
   Keynesian economics, Keynesianism, Lombard Street,
   Wall Street banking, classical economics, dynamic economics, econ,
   econometrics, economic determinism, economic man, economic science,
   economism, finance, finances, high finance, international banking,
   investment banking, money matters, plutology, political economy,
   the dismal science, theoretical economics, world of finance