(n) an annuity paid in a series of more or less equal payments at the beginning of equally spaced periods, Example:rent payable in advance constitutes an annuity in advance for the landlord
The Collaborative International Dictionary of English (GCIDE) v.0.53 Collaborative International Dictionary (GCIDE)
n.; pl.Annuities [ LL. annuitas, fr. L. annus year: cf. F. annuité. ] A sum of money, payable yearly, to continue for a given number of years, for life, or forever; an annual allowance. [ 1913 Webster ]