ETYM Late Lat. annuitas, from Latin annus year: cf. French annuité.
Income from capital investment paid in a series of regular payments; SYN. rente.
Yearly income, especially for life.

ETYM French arrérage, from arričre, Old Fren. arere. Related to Arrear.
That which remains unpaid and overdue, after payment of a part; arrears.