The Collaborative International Dictionary of English v.0.48:

Annuity \An*nu"i*ty\, n.; pl. Annuities. [LL. annuitas, fr. L.
   annus year: cf. F. annuit['e].]
   A sum of money, payable yearly, to continue for a given
   number of years, for life, or forever; an annual allowance.
   [1913 Webster]

Moby Thesaurus II by Grady Ward, 1.0:

77 Moby Thesaurus words for "annuity":
   accident insurance, actuary, aid, alimony, allotment, allowance,
   assistance, assurance, aviation insurance, bail bond, bond, bounty,
   business life insurance, casualty insurance,
   certificate of insurance, court bond, credit insurance,
   credit life insurance, deductible, depletion allowance, dole,
   endowment insurance, family maintenance policy, fellowship,
   fidelity bond, fidelity insurance, financial assistance,
   flood insurance, fraternal insurance, government insurance, grant,
   grant-in-aid, guaranteed annual income, health insurance, help,
   industrial life insurance, insurance, insurance agent,
   insurance broker, insurance company, insurance man,
   insurance policy, interinsurance, liability insurance,
   license bond, limited payment insurance, major medical insurance,
   malpractice insurance, marine insurance, mutual company,
   ocean marine insurance, old-age insurance, pecuniary aid, pension,
   permit bond, policy, price support, public assistance,
   public welfare, relief, retirement benefits, robbery insurance,
   scholarship, social security, stipend, stock company,
   subsidization, subsidy, subvention, support, tax benefit,
   term insurance, theft insurance, underwriter, welfare, welfare aid,
   welfare payments