Source : Webster's Revised Unabridged Dictionary (1913)

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.

Source : WordNet®

annuity
     n : income from capital investment paid in a series of regular
         payments; "his retirement fund was set up to be paid as
         an annuity" [syn: {rente}]