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]